Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
BIOLOGY FORM 5
chapter 1 - Transport
1.2 Circulatory System
Learning Objectives
 1.2 Synthesising the concept of circulatory
system
Function of a circulatory system:
To provide rapid mass flow of
materials:
Blood
flow
Vein
from one part
of the body
to an...
On reaching their destination,
materials must be able to:
pass through the walls of the circulatory
system into the organs...
BLOOD
What percent of the
human body is blood?
How much blood do we
contain?
On average 4-6 liters
8%
COMPOSITION OF BLOOD
 Blood consists of a :
Liquid component:
PLASMA
Solid component:
BLOOD CELLS
Blood is:
a liquid tissue made up of several types
of cell which are bathed in plasma
Whole Blood
Sample
Sample Placed in...
Platelets
White blood cells
Red blood cells
plasma
Percentage by volume of:
What is ‘serum’?
plasma without fibrinogen
Plasma can be separated from the
blood cells. How?
Centrifugation
plasma
Plasma is a clear, yellow
fluid
Percentage of water
in plasma :
Substances dissolved in
plasma:
 Glucose
 Amino acids
 ...
Question:
Name the liquid component of blood and list
TWO substances dissolved in it. (3)
Amino acids
Glucose
[any two fro...
Function of plasma:
to provide a medium through which continual
exchange between cells and blood takes place
Blood flow
Bo...
Erytrocytes
Red blood cells
Platelets
Thrombocytes
Leucocytes
White blood cells
Three types of blood cells:
Red blood cells (RBC) are formed
in the red bone marrow of the:
Ribs
Sternum
Vertebrae
RBC are:
 very small and numerous
 disc-shaped (BICONCAVE)
without a nucleus
 contain the red pigment HAEMOGLOBIN
 fun...
About 2 million RBC per second are
made but production is faster at high
altitude. Why?
There is not so much oxygen in the...
RBC
small biconcave discs
  surface area
  efficiency for diffusion
of O2 & CO2
lack a nucleus when
mature
very thi...
RBC are flexible & elastic:
to squeeze through narrow capillaries
Cardiac muscle
and capillary
Erythrocytes in single fil...
RBC make up about half the
volume of blood
i.e. blood has an enormous oxygen-
carrying capacity
Erythrocytes
(45% of tota...
haemoglobin:
 the oxygen-carrying protein pigment
 combines reversibly with O2
RBC: packed with haemoglobin
Haem
Haemog...
Hb + O2 :
- in areas of high O2
concentration
Hb releases the O2 :
- in regions of low
O2 concentration
Oxyhaemoglobin
LOA...
RBC lack mitochondria. Give two
advantages of this.
1. more room for carrying haemoglobin
2. respire anaerobically : do no...
RBC contain the enzyme:
plays a role in CO2
transport
carbonic
anhydrase
Average life span of a RBC: 120 days
 the old and worn out RBC are broken down
in the:
liver
spleen
What forms from the
haemoglobin broken down?
 IRON part: stored in liver
 The rest of the haemoglobin molecule forms
BIL...
Red blood cells are
adapted to carry oxygen:
1. biconcave disc shape offers maximum
surface area for oxygen uptake
2. haem...
Deoxygenated
blood:
Deep red-purple
Oxygenated
blood: Bright red
Red blood cell production
 5-6 million RBC in tiny drop of human blood
 5 liters of blood in body = 25 trillion RBC
pro...
Shape Biconcave Disk
No nuclei
Transports oxygen & carbon dioxide to
and from tissues
5-6 million/mm3
Has haemoglobin (a p...
Animation
Structure and Composition of the blood
Blood
45% blood cells and platelets
Red blood cells White blood cells Platelets
55%...
98% transported as oxyhaemoglobin
2% transported as gas dissolved in plasma
Reversible reaction
Determined by
concentratio...
air sac in
the lung
oxygen
1 as blood flows through the
lungs the haemoglobin in the
red cells picks up oxygen
2 Haemoglob...
Carbon monoxide & haemoglobin
Result:
 O2 does not combine
with Hb & so it is not
transported
Hb + CO
 Hb combines with ...
Carbon dioxide is transported in three ways:
1) 7% dissolved as a gas in the plasma (7%)
3) Reacts with water to form bica...
H+ released:
 combine with haemoglobin
 and make it less able to carry O2
CO2 has this effect because when it
dissolve...
Transport of carbon dioxide
CO2 must not be allowed to accumulate in the
body
it forms an acid in solution that could le...
Carbonic anhydrase in RBC
catalyses reaction to form H2CO3
CO2 forms at the lungs & is exhaled
AT ACTIVE TISSUES AT LUNGS
Transport of carbon dioxide
 In tissue :
CO2
plasma
+ H2O H+ + HCO3
-
enzyme
Transport of carbon dioxide
 In lungs:
CO2 + H2O H+ + HCO3
-
plasma
enzyme
WHITE BLOOD CELLS (WBC)
WHITE BLOOD CELLS (WBC)
 have a nucleus
 larger than RBC
 are less numerous
than RBC
 some live for
months
 most just...
Agranulocytes
Has no granules in
the cytoplasm
Granulocytes
Has granules in the
cytoplasm
LymphocyteMonocyteNeutrophilBaso...
Lecuocytes can be divided:
Granulocytes Agranulocytes
Lymphocyte
Neutrophil
Basophil
Eosinophil
Monocyte
Lobed nucleus
Ova...
All WBC are capable of a:
crawling movement called amoeboid
movement
Neutrophils:
70% of WBCs
Function
 Phagocytise & destroy
bacteria
Lobed
nucleus
First cells to
respond to
infection
Eosinophils:
1.5% of WBCs but numbers
increase with allergic
conditions
Function:
Secrete antihistamine
Eosin-staining
g...
Basophils:
0.5% of all white blood cells
granules stain blue with basic dyes
such as methylene blue
Function:
produce:
...
Monocytes:
spend 30- 40 hours in
the blood then enter the
tissues where they
become macrophages
macrophages:
are phagoc...
Phagocytes are adapted to
engulf bacteria by having:
 an irregular shape
 a lobed nucleus
Phagocytes can
squeeze out of
...
What is ‘inflammation’?
 phagocytes move to an infected area to attack the
microbes
 when this happens the area becomes:...
Lymphocytes:
 produced in:
 thymus gland
 lymphoid tissues
from cells which
originate in the bone
marrow
Lymphocytes:
are rounded
have a small quantity of cytoplasm
Considering the shape of the
lymphocyte, do you expect amoeb...
are found in:
Lymphocytes:
blood
lymph
body tissues
two types occur:
 T cells
 B cells
life span varies from:
 a mat...
Lymphocytes are produced in the
bone marrow :
 and then move into
the lymph nodes
Lymphocytes produce antibodies
in response to antigens
 antibodies are :
 proteins
 specific
antigen: material
foreign ...
Antibodies begin the process of
destruction of the microbe and
phagocytes finish the job
Immunity is
 a natural resistance to infection due to
antibodies
Question:
White blood cells fight microbes. The number
of white blood cells increases to eliminate the
pathogens. Phagocyt...
Platelets:
irregularly shaped
Cell fragments without
nuclei
life span:
 5-9 days before
destruction in liver &
spleen
Platelets are formed from:
special cells (megakaryocytes) in the
bone marrow
Function of Platelets:
start the clotting process
Break in
Capillary
Wall
Clumping
of Platelets Clot forms
Fibrin
fibres
How does clotting take place?
A clot begins to form when platelets
are damaged. Platelets release a
substance (thromboplas...
Clot dries up to form a scab
Blood
clotting
HAEMOPHILIA
is an inherited disease where a person’s
blood takes a very long time to clot
Blood clot formation needs a cl...
Practical work to include the microscopic
examination of stained
blood films and the identification of cells.
LymphocyteNe...
Difference between RBC AND WBC
characteristics RBC WBC
1. SHAPE a) Erythrocytes are
biconcave disc serves to:
• Increase surface area to
volume ratio
• I...
LIFESPAN 120 days
Destroyed by phagocytes
(WBC) in the liver and
spleen(limpa)
A few days by phagocytosis
process
MANUFACT...
FUNCTIONS OF THE BLOOD
TRANSPORT
PROTECTION
HOMEOSTASIS
1. Transport of O2 and CO2
 oxygen is transported from the lungs to all
body cells as oxyhaemoglobin
 CO2 is carried fro...
2. Distribution of digestive products
Digested food
absorbed from the
intestines
the liver through the
hepatic portal vein...
3. Transport of waste products and
toxic substances
 Liver: detoxifies toxic
substances
 Kidney: excretes
wastes
4. Transport of hormones
 from the endocrine gland that produces them
to the target organ
5. Transport of heat
chemical reactions
inside cells
heat
release heat
muscle contraction
Defence is achieved by:
1. Clotting of the
blood by platelets
and fibrinogen
3. Immunity: by
antibodies and
lymphocytes
2....
 HOMEOSTASIS - keeping a constant internal
environment by:
1. keeping a constant body temperature - by
spreading warmth e...
Transport Protection Regulation
O2
CO2
Nutrient
Waste product
Hormones
Antibodies
Blood glucoseAgainst
pathogens
Phagocyto...
END OF PART 1
ARTHROPODS
Arthropod blood is:
colourless
contains no haemoglobin
HAEMOLYMPH
The haemocoel is a network of blood-
filled spaces called sinuses in which the
internal organs are suspended.
Crayfish
Hae...
Haemolymph – insect blood
• Nutrients such as digested food and hormones
diffuse from haemolymph into cells.
• Waste produ...
The insect’s heart is a flexible tube
and runs:
1. longitudinally
through the
thorax & abdomen Heart
2. along the inside o...
13 chambers in
cockroach
Does not possess :
- valves
- musculature
Is a simple tube
A small valve-like opening
through which blood enters
the heart
The dorsal vessel is:
HEART
closed at the
posterior end
op...
Each chamber has a pair of:
muscles
 expand & contract to facilitate the
flow of haemolymph through the
heart
1.The heart pumps blood
into an aorta: branches
into arteries.
2. These arteries open into
a series of blood spaces
collec...
TYPES OF BLOOD VESSELS
Artery Vein
Capillary
Blood from
the heart.
Blood to
the heart.
Vertebrates:
arteries carry
blood away from
the heart
veins carry blood
back to the heart
O2 is carried by
haemoglobin ...
What happens to an artery
when it enters an organ?
Branches into arterioles
and finally into capillaries.
Circulatory System
Veins
Carry blood towards the heart.
Venules
Capillaries join to form venules.
Blood Capillaries
Walls ...
Compare anatomy of:
Artery
Vein
Note the much
thinner walls in
veins.
Artery and Vein
One reason for walls of arteries being thick
and the middle layer being mainly
composed of elastic fibres.
1. To dilate bu...
Capillaries
 are very small - about the
diameter of a red blood cell
Endothelial cells
Capillaries are so thin that RBC
have to squeeze through
Comparison of blood vessels in
structure
Arteries Veins Capillaries
1) Walls have a
thick muscle and
elastic layer
Walls h...
Arteries Veins Capillaries
2) No valves
present
Valves present to
prevent backflow
No valves
One-way flow
When body muscles
contract, they exert
pressure and
squeeze the veins
flat, helping the blood
to return to the heart.
How ...
Veins contain
one-way
valves
Varicose Veins:
Damaged valves
in veins
Explain the presence of valves in leg and arm
veins. (2)
Question:
The contraction of muscles compressing
veins helps push...
Arteries Veins Capillaries
3) Fluid and WBC
cannot pass
through wall
Fluid and WBC
cannot pass
through wall
Fluid without
...
Capillary beds are:
permeable to:
water, ions, small
molecules
impermeable to:
large proteins
Question:
Explain the wide lumen diameter and thin walls
in veins. (2)
Veins can store a large volume of blood inside
thei...
Comparison of blood vessels in
blood composition and flow
Arteries Veins Capillaries
4) Flow is away
from the heart
Flow i...
Arteries Veins Capillaries
5) Oxygenated
blood except
pulmonary artery
Deoxygenated
blood except
pulmonary vein
Mixed
Pulm...
Question:
List ONE function of the arterial
blood vessels (arteries). (2)
To supply oxygen to the body
cells.
Arteries Veins Capillaries
6) Rapid flow Slow flow
Very slow
flow
7) High pressure Low pressure Low pressure
8) Pulse stro...
arteries capillaries Veins
•Carry oxygenated
blood away from the
heart to all parts of
the body
•Except pulmonary
artery
•...
Artheriosclerosis
• a type of cardiovascular disease
• Caused by the buildup of cholesterol within arteries
Figure 42.18a,...
force exerted by circulating blood
on the walls of blood vessels
The pressure of the circulating blood decreases as
blood ...
Label the veins, venules, arteries,
arterioles, and capillaries
Across which vessels do materials diffuse
(cross into and ...
How is blood propelled through
the human circulatory system?
The heart
• A heart is an organ
that generates
pressure to pump the
blood through out
the body
THE HEART
size of fist
weight is about 250-300 g.
is located between the
lungs behind the sternum
and above the diaphra...
The heart is surrounded
by a tough sac:
Its main purpose is to:
 hold and lubricate the
heart
 make sure that it does
no...
Cardiac Muscle is:
the muscle of the heart
strong and thick
Cardiac muscle
composed of spontaneously contracting
cardia...
Cardiac muscle compared to
skeletal muscle
Cardiac muscle
 contracts more slowly
 does not fatigue as easily
Skeletal mu...
supply heart muscle
can become blocked
By-pass
graft
Damage that occurs when a coronary
artery feeding the heart is blocked
What is a heart attack?
Right coronary
artery
Aorta...
Blocking of a blood vessel by
cholesterol
Blocked coronary
artery leads to a
heart attack
Dead muscle
tissue due to
lack o...
Question:
Suggest TWO ways in which a person’s lifestyle
might lead to a blockage of the coronary
arteries.
1. Lack of exe...
What happens to the blood pressure
if a blood vessel is blocked?
Normal blood flow
Abnormal
blood flow
What is a ‘stroke’?
 Interruption of oxygen supply to the brain
 Caused by:
A clot in an artery
in the brain
Breakage ...
The heart has four chambers
atria  Two upper chambers: atria / auricles
 Two lower chambers: ventricles
ventricles
A wal...
2 advantages of having complete
separation of oxygenated and
deoxygenated blood :
1. Blood reaching the tissues has the hi...
2. Respiratory gas exchange is maximised as
blood with:
 lowest O2 &
 highest CO2 content
is sent to the lungs
Four valves in the
heart:
Pulmonary
semilunar
valveAortic
semilunar
valve
Tricuspid
valve
Bicuspid / mitral
valve
Tricuspi...
Four valves in the heart
Tricuspid valve:
Prevents backflow
to right atrium
Bicuspid valve:
Prevents backflow
to left atri...
SEMILUNAR VALVE
Chorda tendinae
Chordae
tendineae
support
bicuspid valve
Papillary
muscles
Parts of the heart
Atria:
Receiving Chambers
Ventricles:
Pumping Chambers
Valves:
Control one way flow
Septum
Divides the ...
Vertical section: the heart
Aorta
Pulmonary vein
Left atrium
Right atrium
Vena cava
Tricuspid
valve
Pulmonary artery
Right...
The superior & inferior vena cava
return blood to the right atrium
Brings blood from
the upper part
of the body
Brings blo...
Thickness of cardiac
muscle varies according to
the function of the chamber
Atria are thin walled:
deliver blood to adjace...
Right ventricle has thinner
walls than left ventricle
Right ventricle pumps blood to lungs which are
near to heart but lef...
Question:
Give a biological explanation for
each of the following.
Blood pressure is highest in the
arteries and lowest in...
Artificial Heart
Draw the heart
END OF PART 2
The cardiac cycle [0.8s long] is:
the sequence of events which takes place during
the completion of one heartbeat
1 2 3
It takes about 0.8s (~1 min.) for blood
to make 1 complete cycle
Systole: contraction
Diastole: relaxation
Length of time spent at each
phase:
1
2
3
Sequence of events
1.Atrial diastole
Atria and ventricles are
relaxed.
Blood returning to the
heart under low pressure
i...
2. Atrial systole.
Atria contract / Ventricles relax
the two atria
contract
simultaneously.
3. Ventricular systole.
Ventricles contract / atria relax
3. Ventricular systole.
Closure of the AV valves during
ventricular systole produces the first
heart sound: ‘lub’.
AV val...
Ventricles contract
Atria relax
Atria contract
Ventricles relax
When ventricles
contract blood moves:
out of the heart
Whe...
4. Ventricular
diastole.
Ventricles relax.
 The high pressure developed in the aorta and
pulmonary artery:
 tends to fo...
4. Ventricular diastole.
The closing of the semilunar valves
causes the second heart sound, ‘dub’
Semilunar valves
CLOSED
Two normal heart
sounds with each
heart beat:
Sounds of heartbeat are from:
turbulence in blood flow caused by
valve closu...
The events of the cardiac cycle
Cardiac muscle is able to
contract on its own:
A heart removed from a mammal
continues to beat rhythmically
for a consider...
The heart beat originates in the
cardiac muscle: in the
Pacemaker
(sinoatrial node – SA node)
Called pacemaker because:
 ...
Artificial
pacemaker is needed
if heartbeat is slow
The SA node generates waves of
excitation, 70-80 times/ min:
Location: wall of the right atrium near
the entrance of the ...
Once contraction has begun: it spreads
through the walls of the atria [at 1 ms-1]
Excitation spreads to the
AV node
both ...
Tissues of AV node are
similar to SA node AV node supplies
the bundle of His
bundle of His:
provides the only route for th...
Bundle of His consists of modified
cardiac fibres that do not contract
fibres of the bundle of His divide into
right & le...
Cardiac Conduction
System includes:
1. Sinoatrial (SA)
node [pacemaker]
2. Atrioventricular
(AV) node
3. Bundle of His
5. ...
The control of heart rhythm
SA node
(pacemaker)
AV node Bundle
branches
Heart
apex
Purkinje
fibres
2
Signals are
delayed
a...
Question:
During exercise the heart pumps out a greater
volume of blood per minute than when the
body is at rest. List TWO...
Nervous control
of heart rate
The
The muscle cells
initiate electrical signals
Activation of
the atria
Slow heartbeat
Fast heartbeat
can alter the rate ...
The heart is controlled by the
autonomic nervous system
Sympathetic NS
heart rate
The autonomic NS:
 controls the involun...
Sympathetic & Parasympathetic
fibres both end on the SA & AV nodes
Parasympathetic
Nerve
[vagus nerve]
Sympathetic Nerve
S...
Hormonal control
of heart rate
Adrenaline
 Secreted by: adrenal medulla
 When a person is excited, an
increase in the secretion of
adrenaline causes th...
Heart rate increases when
there’s:
Increase in partial pressure of CO2 in
the blood
Body temperature is elevated
force exerted by circulating blood
on the walls of blood vessels
The pressure of the circulating blood decreases as
blood ...
Regulatory mechanism of blood
pressure
• Arterial blood pressure is highest during
ventricular systole , and lowest during...
Blood Pressure
Two reasons why pressure in the RIGHT
VENTRICLE is much lower than that in the
left ventricle:
1. prevent stress on
the ca...
A ‘pulse’ is caused by:
ventricular systole & the elastic recoil of
the arteries as blood at high pressure is
forced throu...
Blood pressure
Systolic
pressure =
pressure when
the heart
contracts.
Diastolic
pressure =
pressure
between heart
beats ...
SPHYGMOMANOMETER
Measure blood pressure.
Measurement of blood pressure
Baroreceptors
Baroreceptors =
pressure receptors
• Normal bp is 120/80 mmHg
• 120 mmHg = systolic
pressure
• 80 mmHg = dia...
Measurement of blood pressure
hypertension =
(high blood pressure)
if systolic > 150
or
if diastolic > 90
The overall nervous control of
the cardiovascular system is located in
the medulla oblongata
Brain stem Spinal cord
Increase in BP
Increase in BP
stretches baroreceptors
impulse cardiovascular centre (medulla)
impulse via parasympathe...
Decrease in BP
sympathetic nerve increases stimulation
of SA node
contraction of cardiac muscles (heart)
& smooth muscles...
As the blood flows through the blood
vessels it is “resisted” by the vessel wall:
if the vessel is:
WIDE [vasodilation]:
...
END OF PART 3
Circulatory System
Regents Biology
Circulatory systems
 All animals have:
 muscular pump = heart
 tubes = blood vessels
 circulatory flui...
Types of circulatory systems
• Open circulatory system : fluid is
circulated through an open body
chamber.
• Closed circul...
Open Circulatory System
Examples of Animals with an
Open Circulatory System
 clams
 Crayfish, shrimp,
lobsters (not
shown)
 insects as
exceptio...
OPEN CIRCULATORY SYSTEM
Arthropoda
Closed system
• Vertebrates, annelid
worms, and a few
mollusks have a
closed circulatory
system.
• Blood is moved
through ...
Examples of Animals with a
Closed Circulatory System
 vertebrates from
fish to mammals
Regents Biology
fish amphibian reptiles birds & mammals
A A
V
V V VV
A AAA
A
V
2 chamber 3 chamber 3 chamber 4 chamber
Clo...
Regents Biology
 increase body size
 fuel warm-blooded
 enable flight
 Higher energy needs
 greater need for energy,
...
Two-chambered heart
• The simplest
vertebrate heart is the
two-chambered heart,
seen in fishes.
• A single atrium
receives...
Three-chambered heart
• Separate atria allow
some separation of
oxygenated and
deoxygenated blood,
which was an advantage
...
Four-chambered heart
• The four-chambered
heart, seen in birds and
mammals, allows
complete separation of
oxygenated and
d...
Single
circulation
Double
circulation
FISH
BIRDS & MAMMALS
have true double
circulations
Human blood circulation:
1. It is a double circulation.
 blood passes
through the heart
twice for each
circuit of the body
Double circulation: blood passes twice
through the heart for each circuit of the body
Pulmonary circulation:
Heart-lungs-h...
Double circulation is
found in:
 birds
 mammals
Why is a single circulation less efficient
than a double circulation?
Drop in pressure
as blood passes
through the gills
AMPHIBIANS
Images from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates
(www.sinauer.com) and WH Freem...
Images from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates
(www.sinauer.com) and WH Freem...
HUMANS , MAMMALS
Images from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates
(www.sinauer.com) and WH Freem...
Comparison of Circulatory Systems
 Explain why a baby born with a hole in its
heart tires very easily.
Deoxygenated blood from the right atrium flows into
...
 Draw schematic figure and compare
circulation system in fish, amphibian and
mammals
PRACTICE
QUICK CHECK 1.2 PG 17
THE END
A. Structure and Composition of
the bloodBlood
55% plasma 45% blood cells and platelets
90% water 10% dissolved substances...
A. Structure and Composition of
the bloodBlood
45% blood cells and platelets
Red blood cells
White blood cells
Platelets
5...
A. Structure and Composition of
the bloodBlood
45% blood cells and platelets
Red blood cells White blood cells Platelets
5...
A. Structure and Composition of
the bloodBlood
45% blood cells and platelets
Red blood cells White blood cells Platelets
5...
A. Structure and Composition of
the bloodBlood
45% blood cells and platelets
Red blood cells White blood cells Platelets
5...
A. Structure and Composition of
the bloodBlood
45% blood cells and platelets
Red blood cells White blood cells Platelets
5...
A. Structure and Composition of
the bloodBlood
45% blood cells and platelets
Red blood cells White blood cells Platelets
5...
A. Structure and Composition of
the bloodBlood
45% blood cells and platelets
Red blood cells White blood cells Platelets
5...
A. Structure and Composition of
the bloodBlood
45% blood cells and platelets
Red blood cells White blood cells Platelets
5...
A. Structure and Composition of
the bloodBlood
45% blood cells and platelets
Red blood cells White blood cells Platelets
5...
A. Structure and Composition of
the bloodBlood
45% blood cells and platelets
Red blood cells White blood cells Platelets
5...
BIOLOGY FORM 5 CHAPTER 1: 1.2  CIRCULATORY SYSTEM
BIOLOGY FORM 5 CHAPTER 1: 1.2  CIRCULATORY SYSTEM
BIOLOGY FORM 5 CHAPTER 1: 1.2  CIRCULATORY SYSTEM
BIOLOGY FORM 5 CHAPTER 1: 1.2  CIRCULATORY SYSTEM
BIOLOGY FORM 5 CHAPTER 1: 1.2  CIRCULATORY SYSTEM
BIOLOGY FORM 5 CHAPTER 1: 1.2  CIRCULATORY SYSTEM
BIOLOGY FORM 5 CHAPTER 1: 1.2  CIRCULATORY SYSTEM
BIOLOGY FORM 5 CHAPTER 1: 1.2  CIRCULATORY SYSTEM
BIOLOGY FORM 5 CHAPTER 1: 1.2  CIRCULATORY SYSTEM
BIOLOGY FORM 5 CHAPTER 1: 1.2  CIRCULATORY SYSTEM
Upcoming SlideShare
Loading in …5
×

BIOLOGY FORM 5 CHAPTER 1: 1.2 CIRCULATORY SYSTEM

27,756 views

Published on

BIOLOGY FORM 5 CHAPTER 1: 1.2 CIRCULATORY SYSTEM

Published in: Education
  • Greek Ritual REVERSES Diabetes (do this before bed) Before you go to bed tonight, do this ONE "stupidly simple" Greek ritual to reverse your diabetes... ➤➤ https://bit.ly/2n5cFHd
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here

BIOLOGY FORM 5 CHAPTER 1: 1.2 CIRCULATORY SYSTEM

  1. 1. BIOLOGY FORM 5 chapter 1 - Transport 1.2 Circulatory System
  2. 2. Learning Objectives  1.2 Synthesising the concept of circulatory system
  3. 3. Function of a circulatory system: To provide rapid mass flow of materials: Blood flow Vein from one part of the body to another over distances where diffusion would be too slow
  4. 4. On reaching their destination, materials must be able to: pass through the walls of the circulatory system into the organs or tissues
  5. 5. BLOOD What percent of the human body is blood? How much blood do we contain? On average 4-6 liters 8%
  6. 6. COMPOSITION OF BLOOD  Blood consists of a : Liquid component: PLASMA Solid component: BLOOD CELLS
  7. 7. Blood is: a liquid tissue made up of several types of cell which are bathed in plasma Whole Blood Sample Sample Placed in Centrifuge Blood Sample That Has Been Centrifuged Plasma Platelets White blood cells Red blood cells
  8. 8. Platelets White blood cells Red blood cells plasma Percentage by volume of:
  9. 9. What is ‘serum’? plasma without fibrinogen
  10. 10. Plasma can be separated from the blood cells. How? Centrifugation plasma
  11. 11. Plasma is a clear, yellow fluid Percentage of water in plasma : Substances dissolved in plasma:  Glucose  Amino acids  Vitamins  Minerals  Lactic acid Layering of blood components in a centrifuged blood sample. 90%  Hormones  Urea  Respiratory gases  Antibodies  Proteins 10%
  12. 12. Question: Name the liquid component of blood and list TWO substances dissolved in it. (3) Amino acids Glucose [any two from previous list. FOOD is wrong] PLASMA
  13. 13. Function of plasma: to provide a medium through which continual exchange between cells and blood takes place Blood flow Body cells
  14. 14. Erytrocytes Red blood cells Platelets Thrombocytes Leucocytes White blood cells Three types of blood cells:
  15. 15. Red blood cells (RBC) are formed in the red bone marrow of the: Ribs Sternum Vertebrae
  16. 16. RBC are:  very small and numerous  disc-shaped (BICONCAVE) without a nucleus  contain the red pigment HAEMOGLOBIN  function of RBC: to transport oxygen & some carbon dioxide
  17. 17. About 2 million RBC per second are made but production is faster at high altitude. Why? There is not so much oxygen in the air.
  18. 18. RBC small biconcave discs   surface area   efficiency for diffusion of O2 & CO2 lack a nucleus when mature very thin cells: efficient diffusion of gases across surface
  19. 19. RBC are flexible & elastic: to squeeze through narrow capillaries Cardiac muscle and capillary Erythrocytes in single file – capillary is so narrow
  20. 20. RBC make up about half the volume of blood i.e. blood has an enormous oxygen- carrying capacity Erythrocytes (45% of total blood) Plasma (55% of total blood) Leucocytes & Platelets (< 1% of total blood)
  21. 21. haemoglobin:  the oxygen-carrying protein pigment  combines reversibly with O2 RBC: packed with haemoglobin Haem Haemoglobin
  22. 22. Hb + O2 : - in areas of high O2 concentration Hb releases the O2 : - in regions of low O2 concentration Oxyhaemoglobin LOADING UNLOADING
  23. 23. RBC lack mitochondria. Give two advantages of this. 1. more room for carrying haemoglobin 2. respire anaerobically : do not use up any of the O2 they carry
  24. 24. RBC contain the enzyme: plays a role in CO2 transport carbonic anhydrase
  25. 25. Average life span of a RBC: 120 days  the old and worn out RBC are broken down in the: liver spleen
  26. 26. What forms from the haemoglobin broken down?  IRON part: stored in liver  The rest of the haemoglobin molecule forms BILE PIGMENTS  bile pigments are excreted in bile Gall bladder stores bile
  27. 27. Red blood cells are adapted to carry oxygen: 1. biconcave disc shape offers maximum surface area for oxygen uptake 2. haemoglobin has a high AFFINITY for oxygen and combines with it, forming OXYHAEMOGLOBIN 3. no nucleus = more space for haemoglobin 4. being small makes it possible for oxygen to enter and leave the RBC quickly
  28. 28. Deoxygenated blood: Deep red-purple Oxygenated blood: Bright red
  29. 29. Red blood cell production  5-6 million RBC in tiny drop of human blood  5 liters of blood in body = 25 trillion RBC produce ~3 million RBC every second in bone marrow to replace cells lost each RBC 250,000 molecules hemoglobin each Hb molecule carries 4 O2 each RBC carries 1 million O2
  30. 30. Shape Biconcave Disk No nuclei Transports oxygen & carbon dioxide to and from tissues 5-6 million/mm3 Has haemoglobin (a pigment) Produced in the bone marrow Life span 120 days Produces enzyme carbonic anhydrase I THINK MAP
  31. 31. Animation
  32. 32. Structure and Composition of the blood Blood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma Structure - No nucleus (Function: more space for haemoglobin) - Haemoglobin pigment (Function: ) - Circular, flattened biconcave disc (Function: ) - Elastic, can become bell-shaped (Function: Squeeze through blood vessels)
  33. 33. 98% transported as oxyhaemoglobin 2% transported as gas dissolved in plasma Reversible reaction Determined by concentration of oxygen, the pH of blood etc. Haemoglobin Oxyhaemoglobin O₂ from lungs O₂ to body tissues
  34. 34. air sac in the lung oxygen 1 as blood flows through the lungs the haemoglobin in the red cells picks up oxygen 2 Haemoglobin and oxygen join to make oxyhaemoglobin 3 when the blood flows past cells with very little oxygen in them the oxyhaemoglobin breaks down oxygen diffuses into the cells of the body oxygen is used for respiration 4 the haemoglobin in the red cells goes back to the lungs to pick up more oxygen
  35. 35. Carbon monoxide & haemoglobin Result:  O2 does not combine with Hb & so it is not transported Hb + CO  Hb combines with any CO available in preference to O2 [a relatively stable compound carboxyhaemoglobin] HbCO RBC do not carry oxygen to the cells Result: The strength of the bond with CO is 10 times that of the bond with 02
  36. 36. Carbon dioxide is transported in three ways: 1) 7% dissolved as a gas in the plasma (7%) 3) Reacts with water to form bicarbonate ions (70%) 2) Bind to Haemoglobin to produce carbaminohaemoglobin (23%)
  37. 37. H+ released:  combine with haemoglobin  and make it less able to carry O2 CO2 has this effect because when it dissolves it forms a weak acid: How does CO2 make Hb release O2?
  38. 38. Transport of carbon dioxide CO2 must not be allowed to accumulate in the body it forms an acid in solution that could lead to fatal changes in blood pH BECAUSE Carbonic acid
  39. 39. Carbonic anhydrase in RBC catalyses reaction to form H2CO3
  40. 40. CO2 forms at the lungs & is exhaled AT ACTIVE TISSUES AT LUNGS
  41. 41. Transport of carbon dioxide  In tissue : CO2 plasma + H2O H+ + HCO3 - enzyme
  42. 42. Transport of carbon dioxide  In lungs: CO2 + H2O H+ + HCO3 - plasma enzyme
  43. 43. WHITE BLOOD CELLS (WBC)
  44. 44. WHITE BLOOD CELLS (WBC)  have a nucleus  larger than RBC  are less numerous than RBC  some live for months  most just a few days
  45. 45. Agranulocytes Has no granules in the cytoplasm Granulocytes Has granules in the cytoplasm LymphocyteMonocyteNeutrophilBasophilEosinophil Produced in the bone marrow Colourless Have nuclei
  46. 46. Lecuocytes can be divided: Granulocytes Agranulocytes Lymphocyte Neutrophil Basophil Eosinophil Monocyte Lobed nucleus Oval or bean-shaped nucleus 72% of total WBC count 28%
  47. 47. All WBC are capable of a: crawling movement called amoeboid movement
  48. 48. Neutrophils: 70% of WBCs Function  Phagocytise & destroy bacteria Lobed nucleus First cells to respond to infection
  49. 49. Eosinophils: 1.5% of WBCs but numbers increase with allergic conditions Function: Secrete antihistamine Eosin-staining granules
  50. 50. Basophils: 0.5% of all white blood cells granules stain blue with basic dyes such as methylene blue Function: produce:  heparin (anti-clotting protein)  histamine (involved in inflammation)
  51. 51. Monocytes: spend 30- 40 hours in the blood then enter the tissues where they become macrophages macrophages: are phagocytic
  52. 52. Phagocytes are adapted to engulf bacteria by having:  an irregular shape  a lobed nucleus Phagocytes can squeeze out of capillaries.
  53. 53. What is ‘inflammation’?  phagocytes move to an infected area to attack the microbes  when this happens the area becomes:  red  swollen  hot INFLAMMATION  pus may form Pus = accumulation of WBC + microbes
  54. 54. Lymphocytes:  produced in:  thymus gland  lymphoid tissues from cells which originate in the bone marrow
  55. 55. Lymphocytes: are rounded have a small quantity of cytoplasm Considering the shape of the lymphocyte, do you expect amoeboid movement to be extensive or limited? Limited
  56. 56. are found in: Lymphocytes: blood lymph body tissues two types occur:  T cells  B cells life span varies from:  a matter of days  to many years involved in immune reactions
  57. 57. Lymphocytes are produced in the bone marrow :  and then move into the lymph nodes
  58. 58. Lymphocytes produce antibodies in response to antigens  antibodies are :  proteins  specific antigen: material foreign to the body e.g. a bacterium or virus
  59. 59. Antibodies begin the process of destruction of the microbe and phagocytes finish the job
  60. 60. Immunity is  a natural resistance to infection due to antibodies
  61. 61. Question: White blood cells fight microbes. The number of white blood cells increases to eliminate the pathogens. Phagocytes engulf and digest harmful bacteria while lymphocytes produce antibodies. Briefly explain why the presence of a large number of white blood cells in a blood sample, is an indication of the presence of an infectious disease. (3)
  62. 62. Platelets: irregularly shaped Cell fragments without nuclei life span:  5-9 days before destruction in liver & spleen
  63. 63. Platelets are formed from: special cells (megakaryocytes) in the bone marrow
  64. 64. Function of Platelets: start the clotting process Break in Capillary Wall Clumping of Platelets Clot forms Fibrin fibres
  65. 65. How does clotting take place? A clot begins to form when platelets are damaged. Platelets release a substance (thromboplastin / thrombokinase). Skin is cut. A series of chemical reactions occur that ends up by producing a meshwork of FIBRIN. 1 2 3
  66. 66. Clot dries up to form a scab
  67. 67. Blood clotting
  68. 68. HAEMOPHILIA is an inherited disease where a person’s blood takes a very long time to clot Blood clot formation needs a clotting factor: missing in haemophiliacs.
  69. 69. Practical work to include the microscopic examination of stained blood films and the identification of cells. LymphocyteNeutrophils Platelets Erythrocytes Monocyte
  70. 70. Difference between RBC AND WBC
  71. 71. characteristics RBC WBC 1. SHAPE a) Erythrocytes are biconcave disc serves to: • Increase surface area to volume ratio • Increase diffusion rate of gaseous exchange b) No nucleus to gives space for great quantities of haemoglobin •Leucocytes have nuclei •Not have haemoglobin •Larger than erythrocytes •Do not have fixed shaped 2.FUNCTION •Has haem group •Contains iron atom •For the site of oxygen binding •When the partial pressure of o2 is high, •Haemoglobin will combine with o2 to form •OXYHAEMOGLOBIN •Responsible for the defense of organism against disease •If pathogen invade the body, number of leucocytes will increase
  72. 72. LIFESPAN 120 days Destroyed by phagocytes (WBC) in the liver and spleen(limpa) A few days by phagocytosis process MANUFACT URED IN Bone marrow Rate: 2 million/ second Bone marrow(granulocytes) •But may migrate to thymus gland or lymph node •For their growth and development stage •Lymphatic system ( agranucolytes) 3. DIAMETER 8 micrometer Thickness: 2 micrometer 15 micro meter 4.Number of blood cell/mm3 5 million/mm3 6000-10000/mm3 (Ration: 1WBC:700RBC)
  73. 73. FUNCTIONS OF THE BLOOD TRANSPORT PROTECTION HOMEOSTASIS
  74. 74. 1. Transport of O2 and CO2  oxygen is transported from the lungs to all body cells as oxyhaemoglobin  CO2 is carried from the body cells to the lungs in three ways: 1. mostly as hydrogen carbonate in plasma (85%) 2. combined with haemoglobin (10-20%) 3. as dissolved carbon dioxide in plasma (5%)
  75. 75. 2. Distribution of digestive products Digested food absorbed from the intestines the liver through the hepatic portal vein whole body
  76. 76. 3. Transport of waste products and toxic substances  Liver: detoxifies toxic substances  Kidney: excretes wastes
  77. 77. 4. Transport of hormones  from the endocrine gland that produces them to the target organ
  78. 78. 5. Transport of heat chemical reactions inside cells heat release heat muscle contraction
  79. 79. Defence is achieved by: 1. Clotting of the blood by platelets and fibrinogen 3. Immunity: by antibodies and lymphocytes 2. Phagocytosis: by neutrophils, monocytes & macrophages
  80. 80.  HOMEOSTASIS - keeping a constant internal environment by: 1. keeping a constant body temperature - by spreading warmth evenly around the body 2. regulating the amounts of various substances in the tissues
  81. 81. Transport Protection Regulation O2 CO2 Nutrient Waste product Hormones Antibodies Blood glucoseAgainst pathogens Phagocytosis Producing Antibodies & Body temperature pH Osmotic pressure
  82. 82. END OF PART 1
  83. 83. ARTHROPODS
  84. 84. Arthropod blood is: colourless contains no haemoglobin HAEMOLYMPH
  85. 85. The haemocoel is a network of blood- filled spaces called sinuses in which the internal organs are suspended. Crayfish Haemoc oel Sinu s
  86. 86. Haemolymph – insect blood • Nutrients such as digested food and hormones diffuse from haemolymph into cells. • Waste products diffuse out from cells into the haemolymph • Haemolymph does not transport respiratory gases. • Gaseous exchange via the tracheal system
  87. 87. The insect’s heart is a flexible tube and runs: 1. longitudinally through the thorax & abdomen Heart 2. along the inside of the dorsal body wall
  88. 88. 13 chambers in cockroach Does not possess : - valves - musculature Is a simple tube
  89. 89. A small valve-like opening through which blood enters the heart The dorsal vessel is: HEART closed at the posterior end open at the anterior end The heart is divided into chambers separated by ostia Heart
  90. 90. Each chamber has a pair of: muscles  expand & contract to facilitate the flow of haemolymph through the heart
  91. 91. 1.The heart pumps blood into an aorta: branches into arteries. 2. These arteries open into a series of blood spaces collectively called the haemocoel. 3. Blood under low pressure moves slowly between the tissues, gradually percolating back into the heart through open-ended veins.
  92. 92. TYPES OF BLOOD VESSELS Artery Vein Capillary Blood from the heart. Blood to the heart.
  93. 93. Vertebrates: arteries carry blood away from the heart veins carry blood back to the heart O2 is carried by haemoglobin in red blood cells
  94. 94. What happens to an artery when it enters an organ? Branches into arterioles and finally into capillaries.
  95. 95. Circulatory System Veins Carry blood towards the heart. Venules Capillaries join to form venules. Blood Capillaries Walls are one cell thick. Partially permeable lining allows substances to diffuse quickly. Slow movement of blood. Heart Relaxed state: heart is filled with blood. Contracting heart: blood is being pumped with great force out to lungs and to rest of body. Arteries Artery carries blood away. Arterioles Branching of arteries.
  96. 96. Compare anatomy of:
  97. 97. Artery Vein Note the much thinner walls in veins. Artery and Vein
  98. 98. One reason for walls of arteries being thick and the middle layer being mainly composed of elastic fibres. 1. To dilate but not rupture when the heart forces blood into them at high pressure
  99. 99. Capillaries  are very small - about the diameter of a red blood cell Endothelial cells
  100. 100. Capillaries are so thin that RBC have to squeeze through
  101. 101. Comparison of blood vessels in structure Arteries Veins Capillaries 1) Walls have a thick muscle and elastic layer Walls have a thin muscle and elastic layer Walls are one cell thick
  102. 102. Arteries Veins Capillaries 2) No valves present Valves present to prevent backflow No valves One-way flow
  103. 103. When body muscles contract, they exert pressure and squeeze the veins flat, helping the blood to return to the heart. How does blood return to the heart?
  104. 104. Veins contain one-way valves Varicose Veins: Damaged valves in veins
  105. 105. Explain the presence of valves in leg and arm veins. (2) Question: The contraction of muscles compressing veins helps push blood up through the leg and arm veins back to the heart. The valves allow the blood to flow towards the heart only.
  106. 106. Arteries Veins Capillaries 3) Fluid and WBC cannot pass through wall Fluid and WBC cannot pass through wall Fluid without proteins can pass through wall. WBC pass out between cells artery vein capillary
  107. 107. Capillary beds are: permeable to: water, ions, small molecules impermeable to: large proteins
  108. 108. Question: Explain the wide lumen diameter and thin walls in veins. (2) Veins can store a large volume of blood inside their wide lumen. Thin walls can easily extend to contain the blood.
  109. 109. Comparison of blood vessels in blood composition and flow Arteries Veins Capillaries 4) Flow is away from the heart Flow is towards the heart Flow is from artery to vein HEART
  110. 110. Arteries Veins Capillaries 5) Oxygenated blood except pulmonary artery Deoxygenated blood except pulmonary vein Mixed Pulmonary artery Vein Artery
  111. 111. Question: List ONE function of the arterial blood vessels (arteries). (2) To supply oxygen to the body cells.
  112. 112. Arteries Veins Capillaries 6) Rapid flow Slow flow Very slow flow 7) High pressure Low pressure Low pressure 8) Pulse strong No pulse No pulse
  113. 113. arteries capillaries Veins •Carry oxygenated blood away from the heart to all parts of the body •Except pulmonary artery •Sites for the exchange of respiratory gases, nutrients and wastes •Transport deoxygenated blood from all parts of the body to the heart except pulmonary vein •Blood pressure: •High blood pressure in arteries •Lower than arteries but higher than veins •Lower than arteries •Thick muscular wall •Lumen size small •One cell thickness •Lumen is very small •Thinner wall •Lumen size is large •No valve except aorta •No valve •Valve present to prevent backflow of blood
  114. 114. Artheriosclerosis • a type of cardiovascular disease • Caused by the buildup of cholesterol within arteries Figure 42.18a, b (a) Normal artery (b) Partly clogged artery 50 µm 250 µm Smooth muscleConnective tissue Endothelium Plaque
  115. 115. force exerted by circulating blood on the walls of blood vessels The pressure of the circulating blood decreases as blood moves away from the heart Blood Pressure refers to the:
  116. 116. Label the veins, venules, arteries, arterioles, and capillaries Across which vessels do materials diffuse (cross into and out of the blood)? Indicate where the heart is vein venules artery arterioles capillaries
  117. 117. How is blood propelled through the human circulatory system?
  118. 118. The heart • A heart is an organ that generates pressure to pump the blood through out the body
  119. 119. THE HEART size of fist weight is about 250-300 g. is located between the lungs behind the sternum and above the diaphragm.
  120. 120. The heart is surrounded by a tough sac: Its main purpose is to:  hold and lubricate the heart  make sure that it does not expand too much.
  121. 121. Cardiac Muscle is: the muscle of the heart strong and thick Cardiac muscle composed of spontaneously contracting cardiac muscle fibres: MYOGENIC image of a single human heart muscle cell beating Myogenic – self-exciting - contractions occur spontaneously
  122. 122. Cardiac muscle compared to skeletal muscle Cardiac muscle  contracts more slowly  does not fatigue as easily Skeletal muscle
  123. 123. supply heart muscle can become blocked By-pass graft
  124. 124. Damage that occurs when a coronary artery feeding the heart is blocked What is a heart attack? Right coronary artery Aorta Left coronary artery Blockage Dead muscle tissue
  125. 125. Blocking of a blood vessel by cholesterol Blocked coronary artery leads to a heart attack Dead muscle tissue due to lack of oxygen
  126. 126. Question: Suggest TWO ways in which a person’s lifestyle might lead to a blockage of the coronary arteries. 1. Lack of exercise. 2. Smoking. 3. Eating food rich in fats. 4. Excessive alcohol intake.
  127. 127. What happens to the blood pressure if a blood vessel is blocked? Normal blood flow Abnormal blood flow
  128. 128. What is a ‘stroke’?  Interruption of oxygen supply to the brain  Caused by: A clot in an artery in the brain Breakage of an artery in the brain  Causes brain cells to be deprived of oxygen and die
  129. 129. The heart has four chambers atria  Two upper chambers: atria / auricles  Two lower chambers: ventricles ventricles A wall / septum separates the two sides. Why? To prevent mixing of deoxygenated blood on the right side from the oxygenated blood on the left. RIGHT LEFT
  130. 130. 2 advantages of having complete separation of oxygenated and deoxygenated blood : 1. Blood reaching the tissues has the highest possible O2 content. Interventricular septum Left ventricle Right ventricle
  131. 131. 2. Respiratory gas exchange is maximised as blood with:  lowest O2 &  highest CO2 content is sent to the lungs
  132. 132. Four valves in the heart: Pulmonary semilunar valveAortic semilunar valve Tricuspid valve Bicuspid / mitral valve Tricuspid valve Bicuspid valve Pulmonary semilunar valve Aortic semilunar valve
  133. 133. Four valves in the heart Tricuspid valve: Prevents backflow to right atrium Bicuspid valve: Prevents backflow to left atrium Semilunar valves: Prevent backflow to ventricles RIGHT LEFT Bicuspid valve Tricuspid valve Semilunar valves
  134. 134. SEMILUNAR VALVE
  135. 135. Chorda tendinae
  136. 136. Chordae tendineae support bicuspid valve Papillary muscles
  137. 137. Parts of the heart Atria: Receiving Chambers Ventricles: Pumping Chambers Valves: Control one way flow Septum Divides the Heart
  138. 138. Vertical section: the heart Aorta Pulmonary vein Left atrium Right atrium Vena cava Tricuspid valve Pulmonary artery Right ventricle Tendon Left ventricle Semi-lunar valves Bicuspid valve
  139. 139. The superior & inferior vena cava return blood to the right atrium Brings blood from the upper part of the body Brings blood from the lower part of the body
  140. 140. Thickness of cardiac muscle varies according to the function of the chamber Atria are thin walled: deliver blood to adjacent ventricles Ventricle walls are much thicker and stronger: Right ventricle supplies blood to the lungs (little flow resistance) Left ventricle wall: thickest to supply blood to all parts of the body except lungs
  141. 141. Right ventricle has thinner walls than left ventricle Right ventricle pumps blood to lungs which are near to heart but left ventricle pumps to whole body. Thus less pressure is needed. Right ventricle Left ventricle
  142. 142. Question: Give a biological explanation for each of the following. Blood pressure is highest in the arteries and lowest in the veins. (4) Highest blood pressure in arteries: blood is pumped into them by heart. Lowest in veins: blood is far away from heart.
  143. 143. Artificial Heart
  144. 144. Draw the heart
  145. 145. END OF PART 2
  146. 146. The cardiac cycle [0.8s long] is: the sequence of events which takes place during the completion of one heartbeat 1 2 3
  147. 147. It takes about 0.8s (~1 min.) for blood to make 1 complete cycle
  148. 148. Systole: contraction Diastole: relaxation
  149. 149. Length of time spent at each phase: 1 2 3
  150. 150. Sequence of events 1.Atrial diastole Atria and ventricles are relaxed. Blood returning to the heart under low pressure in the veins, enters the atria.
  151. 151. 2. Atrial systole. Atria contract / Ventricles relax the two atria contract simultaneously.
  152. 152. 3. Ventricular systole. Ventricles contract / atria relax
  153. 153. 3. Ventricular systole. Closure of the AV valves during ventricular systole produces the first heart sound: ‘lub’. AV valves CLOSED
  154. 154. Ventricles contract Atria relax Atria contract Ventricles relax When ventricles contract blood moves: out of the heart When atria contract blood moves: into the ventricles
  155. 155. 4. Ventricular diastole. Ventricles relax.  The high pressure developed in the aorta and pulmonary artery:  tends to force some blood back towards the ventricles  thus semilunar valves of the aorta and pulmonary artery close.
  156. 156. 4. Ventricular diastole. The closing of the semilunar valves causes the second heart sound, ‘dub’ Semilunar valves CLOSED
  157. 157. Two normal heart sounds with each heart beat: Sounds of heartbeat are from: turbulence in blood flow caused by valve closure
  158. 158. The events of the cardiac cycle
  159. 159. Cardiac muscle is able to contract on its own: A heart removed from a mammal continues to beat rhythmically for a considerable time if placed in a well-oxygenated Ringer solution at 37C, in the absence of stimulation from nerves or hormones. Demonstration of the myogenic nature of the heart:
  160. 160. The heart beat originates in the cardiac muscle: in the Pacemaker (sinoatrial node – SA node) Called pacemaker because:  each wave of excitation begins here  acts as the stimulus for the next wave of excitation
  161. 161. Artificial pacemaker is needed if heartbeat is slow
  162. 162. The SA node generates waves of excitation, 70-80 times/ min: Location: wall of the right atrium near the entrance of the superior vena cava initiates & coordinates contraction of the heart is a cluster of specialised muscle cells that produce spontaneous electrical signals at a regular rate
  163. 163. Once contraction has begun: it spreads through the walls of the atria [at 1 ms-1] Excitation spreads to the AV node both atria contract more or less simultaneously
  164. 164. Tissues of AV node are similar to SA node AV node supplies the bundle of His bundle of His: provides the only route for the transmission of the wave of excitation from the atria to the ventricles bundle of His Location of AV node: Base of right atrium Function of AV node: Connects atria & ventricles electrically
  165. 165. Bundle of His consists of modified cardiac fibres that do not contract fibres of the bundle of His divide into right & left bundle branches bundle of His bundle branches bundle branches:  run to the tips of the ventricles & then spread throughout the ventricles as Purkinje fibres
  166. 166. Cardiac Conduction System includes: 1. Sinoatrial (SA) node [pacemaker] 2. Atrioventricular (AV) node 3. Bundle of His 5. Purkinje fibres 4. Bundle branches
  167. 167. The control of heart rhythm SA node (pacemaker) AV node Bundle branches Heart apex Purkinje fibres 2 Signals are delayed at AV node. 1 SA node generates wave of signals to contract. Signals pass to heart apex. 4 Signals spread throughout ventricles. 1 2 3 4
  168. 168. Question: During exercise the heart pumps out a greater volume of blood per minute than when the body is at rest. List TWO ways in which the heart can increase the volume of blood pumped out. (4) 1. Increase in heart beat rate. 2. Each beat becomes stronger.
  169. 169. Nervous control of heart rate
  170. 170. The The muscle cells initiate electrical signals Activation of the atria Slow heartbeat Fast heartbeat can alter the rate of these signal
  171. 171. The heart is controlled by the autonomic nervous system Sympathetic NS heart rate The autonomic NS:  controls the involuntary functions of the body  has two subdivisions which exert opposite effects: Parasympathetic NS heart rate Rest & digest
  172. 172. Sympathetic & Parasympathetic fibres both end on the SA & AV nodes Parasympathetic Nerve [vagus nerve] Sympathetic Nerve Slows heartbeat Increases heartbeat
  173. 173. Hormonal control of heart rate
  174. 174. Adrenaline  Secreted by: adrenal medulla  When a person is excited, an increase in the secretion of adrenaline causes the heart to beat faster medulla cortex The medulla also secretes smaller amounts of the hormone noradrenaline : has similar effects to adrenaline  both stimulate the heart, but adrenaline is more effective
  175. 175. Heart rate increases when there’s: Increase in partial pressure of CO2 in the blood Body temperature is elevated
  176. 176. force exerted by circulating blood on the walls of blood vessels The pressure of the circulating blood decreases as blood moves away from the heart Blood Pressure refers to the: Regulatory mechanism of blood pressure
  177. 177. Regulatory mechanism of blood pressure • Arterial blood pressure is highest during ventricular systole , and lowest during diastole
  178. 178. Blood Pressure
  179. 179. Two reasons why pressure in the RIGHT VENTRICLE is much lower than that in the left ventricle: 1. prevent stress on the capillaries of the lungs 2. give chance for gaseous exchange to take place
  180. 180. A ‘pulse’ is caused by: ventricular systole & the elastic recoil of the arteries as blood at high pressure is forced through them
  181. 181. Blood pressure Systolic pressure = pressure when the heart contracts. Diastolic pressure = pressure between heart beats (when heart relaxes)
  182. 182. SPHYGMOMANOMETER Measure blood pressure.
  183. 183. Measurement of blood pressure
  184. 184. Baroreceptors Baroreceptors = pressure receptors • Normal bp is 120/80 mmHg • 120 mmHg = systolic pressure • 80 mmHg = diastolic pressure • Blood pressure is regulated by baroreceptors (pressure receptors ) in the walls of the aorta and carotid arteries. • Baroreceptors monitor the pressure of blood flowing to body and brain
  185. 185. Measurement of blood pressure hypertension = (high blood pressure) if systolic > 150 or if diastolic > 90
  186. 186. The overall nervous control of the cardiovascular system is located in the medulla oblongata Brain stem Spinal cord
  187. 187. Increase in BP Increase in BP stretches baroreceptors impulse cardiovascular centre (medulla) impulse via parasympathetic nerve heart heartbeat slows BP drops  BP normal
  188. 188. Decrease in BP sympathetic nerve increases stimulation of SA node contraction of cardiac muscles (heart) & smooth muscles of arteries heartbeat faster BP increases BP normal
  189. 189. As the blood flows through the blood vessels it is “resisted” by the vessel wall: if the vessel is: WIDE [vasodilation]:  resistance is very low  blood pressure is low NARROW [vasoconstriction]:  resistance is high  blood pressure is high
  190. 190. END OF PART 3
  191. 191. Circulatory System
  192. 192. Regents Biology Circulatory systems  All animals have:  muscular pump = heart  tubes = blood vessels  circulatory fluid = “blood” open closed hemolymph blood
  193. 193. Types of circulatory systems • Open circulatory system : fluid is circulated through an open body chamber. • Closed circulatory system : fluid is circulated through blood vessels.
  194. 194. Open Circulatory System
  195. 195. Examples of Animals with an Open Circulatory System  clams  Crayfish, shrimp, lobsters (not shown)  insects as exception to low oxygen use rule (remember the tracheal system)
  196. 196. OPEN CIRCULATORY SYSTEM Arthropoda
  197. 197. Closed system • Vertebrates, annelid worms, and a few mollusks have a closed circulatory system. • Blood is moved through blood vessels by the heart’s action. It does not come in direct contact with body organs.
  198. 198. Examples of Animals with a Closed Circulatory System  vertebrates from fish to mammals
  199. 199. Regents Biology fish amphibian reptiles birds & mammals A A V V V VV A AAA A V 2 chamber 3 chamber 3 chamber 4 chamber Closed Circulatory System Blood only flows in blood vessels
  200. 200. Regents Biology  increase body size  fuel warm-blooded  enable flight  Higher energy needs  greater need for energy, fuel, O2, waste removal  warm-blooded animals & flying need 10x energy  need to deliver 10x fuel & O2 What advantage has a 4-chambered heart?
  201. 201. Two-chambered heart • The simplest vertebrate heart is the two-chambered heart, seen in fishes. • A single atrium receives blood from the body cells. A ventricle sends blood to the gills to collect oxygen.
  202. 202. Three-chambered heart • Separate atria allow some separation of oxygenated and deoxygenated blood, which was an advantage for land organisms (reptiles, amphibians). • Though blood can mix in the ventricle, mixing is minimal. Some reptiles have partial separation of the ventricle.
  203. 203. Four-chambered heart • The four-chambered heart, seen in birds and mammals, allows complete separation of oxygenated and deoxygenated blood. • Complete separation is necessary to support a fast metabolism found in homeotherms.
  204. 204. Single circulation Double circulation FISH BIRDS & MAMMALS have true double circulations
  205. 205. Human blood circulation: 1. It is a double circulation.  blood passes through the heart twice for each circuit of the body
  206. 206. Double circulation: blood passes twice through the heart for each circuit of the body Pulmonary circulation: Heart-lungs-heart Systemic circulation: Heart-body-heart
  207. 207. Double circulation is found in:  birds  mammals
  208. 208. Why is a single circulation less efficient than a double circulation? Drop in pressure as blood passes through the gills
  209. 209. AMPHIBIANS
  210. 210. Images from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)
  211. 211. Images from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)
  212. 212. HUMANS , MAMMALS
  213. 213. Images from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)
  214. 214. Comparison of Circulatory Systems
  215. 215.  Explain why a baby born with a hole in its heart tires very easily. Deoxygenated blood from the right atrium flows into the left atrium where it mixes with oxygenated blood. The aorta carries this mixture to the muscles. The muscles do not receive enough oxygen. Adult heart Foetal heart
  216. 216.  Draw schematic figure and compare circulation system in fish, amphibian and mammals PRACTICE
  217. 217. QUICK CHECK 1.2 PG 17
  218. 218. THE END
  219. 219. A. Structure and Composition of the bloodBlood 55% plasma 45% blood cells and platelets 90% water 10% dissolved substances Antibodies Digested food Mineral salts Proteins for blood clotting Excretory products (Pale yellowish liquid) Amounts kept relatively constant
  220. 220. A. Structure and Composition of the bloodBlood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma
  221. 221. A. Structure and Composition of the bloodBlood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma = Erythrocytes = Leukocytes/leucocytes = Thrombocytes
  222. 222. A. Structure and Composition of the bloodBlood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma - Ave 5 million/cm3 of blood (varies with gender and health) - Produced by bone marrow - Each cell lives about 3-4 months - Destroyed in the ____________ - Haemoglobin broken down in the ______________
  223. 223. A. Structure and Composition of the bloodBlood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma Structure - What do you remember about its structure?
  224. 224. A. Structure and Composition of the bloodBlood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma Structure - No nucleus (Function: more space for haemoglobin) - Haemoglobin pigment (Function: ) - Circular, flattened biconcave disc (Function: ) - Elastic, can become bell-shaped (Function: Squeeze through blood vessels)
  225. 225. A. Structure and Composition of the bloodBlood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma - Larger in size than erythrocytes, but fewer in number - Ave 5000-10000/cm3 of blood - Colourless (no haemoglobin) - Most are also produced by bone marrow
  226. 226. A. Structure and Composition of the bloodBlood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma Structure - Irregular in shape - Has a nucleus - Can move and change shape (Function: )
  227. 227. A. Structure and Composition of the bloodBlood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma 2 main types - Phagocytes (different types have different names) - Lymphocytes - Function: To help the body fight disease
  228. 228. A. Structure and Composition of the bloodBlood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma - Phagocytes - Structure: Nuclei have lobes and cytoplasm is granular - Function: Engulf, ingest and digest foreign particles - Lymphocytes - Structure: Nuclei are large and round (no lobes), cytoplasm is non-granular - Function: Produce antibodies
  229. 229. A. Structure and Composition of the bloodBlood 45% blood cells and platelets Red blood cells White blood cells Platelets 55% plasma - Not true cells - But classified with cells when talking about composition of blood - Membrane-bound fragments of cytoplasm - Produced by bone marrow - Function: Involved in blood clotting

×