Circulatory Shock, types and stages, compensatory mechanisms
1.Introduction to human physiology-1 (1).pptx
1. Introduction to Human Physiology
For Pharmacy students
By Yibeltal Y (MSc in Medical Physiology)
Email: yibeltalyismaw7@gmail.com
Department of Human Physiology
4/9/2024
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3. Presentation Outline
Introduction
Homeostasis
Control systems
Control mechanisms
Negative feedback control systems
Positive feedback mechanisms
Communications between cells (types of
junctions)
Cell structure and function
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4. Objectives
At the end of this chapter the students will be able to:
1. Explain homeostasis.
2. Discuss negative & positive feed back mechanism.
3. Define physiology
4. Discuss cell physiology.
5. Enumerate the cell organelles with their function.
6. List the types of cellular transport
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5. General Introduction
What is Physiology? Two Greek words: Physis: nature, origin, Logia:
study of
Physiology is the science that seeks to explain the physical and
chemical mechanisms that are responsible for the Origin,
Development, and Progression of life
Each type of life, from the simplest virus to the largest complicated
human being, has its own functional characteristics.
Therefore, the vast field of physiology can be divided into
Viral physiology, bacterial physiology, cellular physiology, plant
physiology, invertebrate physiology, vertebrate physiology,
mammalian physiology, Human Physiology, & many more
subdivisions.
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6. General introduction cont’d…
Physiology is the study of functionality of living organisms at the
cellular, organ and systemic levels.
Historical background
Aristotle (384 - 322 B.C.) was
The father of natural history &
The 1st person to coin the term physiology.
According to Aristotle, Physiology meant the study of nature-
“Physio - nature, logus - study.
This means studying practically everything in the Universe and
in the human body.
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7. General introduction
William Harvey in 1628,
Correctly described the direction of circulation of blood
Described that the heart pumps blood, arteries transport oxygenated
blood, exchange of substances occur at the systemic capillaries and
veins return deoxygenated blood.
For this reason he is known to be
the father of physiology.
Claud Bernard,
a French physiologist in the 19th C. described that every cell
in body is bathed with the fluid environment called ECF.
ECF contains all the needed substances for cells.
He called ECF is the internal environment of the body.
Walter cannon,
another great physiologist of the 1st half of 19th century, termed the
maintenance of nearly constant conditions in the ECF as
homeostasis
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8. Relation of physiology with other sciences
o Physiology is closely related to several other branches of
science such as anatomy, pharmacology, biochemistry,
pathology etc.
o Therefore, Physiology is not an isolated science, but highly
associated with other sciences.
o Physiology as a quantitative science
-All physiological parameters are expressed in numbers
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11. Extracellular Fluid
Cell is the basic structural & functional unit of life.
The human organism consists of 100 trillions of cells.
for the maintenance of the entire organism
These cells are bathed with the fluid that is called ECF
(fluid that fills the space between cells).
About 60% of the adult human body is fluid, mainly the
water solution of ions and other substances.
Although most of this fluid is inside the cells(2/3th) & is
called intracellular fluid-ICF, about one third is in the
spaces outside the cells and is called extracellular fluid.
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12. Internal environment cont’d…”
This extracellular fluid is in constant motion throughout the
body.
It is transported rapidly in the circulating blood and then mixed
between the blood and the tissue fluids by diffusion through the
capillary walls.
In the extracellular fluid are the ions and nutrients needed by the
cells to maintain life.
While cells may perform very different functions, all the cells are
quite similar in their metabolic requirements:
Oxygen , Glucose, Mineral ions, Waste removal …
Thus, all cells live in essentially the same environment the
extracellular fluid.
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13. internal environment cont’d…
For this reason, the extracellular fluid is also called the internal
environment of the body, or the milieu intérieur, a term
introduced by the great 19th-century French physiologist Claude
Bernard (1813–1878).
Cells are capable of living and performing their special functions
as long as
The proper concentrations of gases ,oxygen, glucose, different ions,
amino acids, fatty substances, hormones, enzymes, water & electrolytes
and other constituents are available in this internal environment.
Therefore, Maintaining a nearly constant internal environment is
necessary for the well-being of individual cells & the well-being
of the entire body
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14. Extracellular VS Intracellular Fluids
The extracellular fluid contains large amounts of
Sodium, chloride, and Bicarbonate ions plus
Nutrients for the cells, such as oxygen, glucose, fatty acids, and amino
acids.
It also contains
Carbon Dioxide that is being transported from the cells to the lungs to be
excreted, plus
Other cellular waste products that are being transported to the kidneys
for excretion.
The intracellular fluid differs significantly from the extracellular fluid; for
example, it contains
Large amounts of potassium, magnesium, and phosphate ions instead
of the sodium and chloride ions found in the extracellular fluid.
Special mechanisms for transporting ions through the cell membranes
maintain the ion concentration differences between the extracellular
and intracellular fluids.
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15. Homeostasis
Gk homoios (same) & stasis (standing still)
It is maintenance of nearly static or constant conditions in
the internal environment (ECF).
Essentially all organs of the body perform their functions to
maintain constant conditions in the ECF.
For example
Lungs maintain the normal concentration of respiratory
gases in blood.
The CVS transports required substances and removes waste
produces,
The kidneys maintain constant ionic concentration and
The GIT provides nutrients.
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16. Homeostasis cont’d…
Homeostasis in a general sense refers to:
Stability, balance or equilibrium.
Maintaining a stable internal environment requires constant
monitoring & adjustments as conditions change.
Adjustment of physiological systems within the body is called
homeostatic regulation; which involves 3 parts or mechanisms:
Receptor, Control Centre & Effector
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17. Homeostasis…cont’d
1. Receptor
Receives information that something in the environment
is changing.
2. Control center or integration center
Receives & processes information from the receptor.
3. Effector
Responds to the commands of the control center by
either opposing or enhancing the stimulus.
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18. Homeostasis…cont’d
Homeostatic regulation is an ongoing process that
continually works to restore & maintain homeostasis.
For example
In regulating body temperature there are
temperature receptors in the skin,
Which communicate information to the brain,
which is the control center, &
The effector is our blood vessels and sweat glands.
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19. Homeostasis…cont’d
Homeostatically regulated variables
Body Temperature
Blood Composition
Ions, sugars, proteins, water,
O2 and CO2 , PH & Osmolality
Blood Pressure,
Cardiac Output, Cardiac Rate
Respiratory Rate and depth
Secretions of Endocrine Glands
Rate of intracellular chemical reactions
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20. Homeostasis…cont’d
Factors Disrupting Homeostasis:
External stimuli
Heat, cold,
Lack of O2,
Pathogens & Toxins
Internal stimuli
Abnormalities in visceral organs
Function of homeostasis
It allows an organism to function effectively in a broad
range of environmental conditions
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21. Stimulus:
Produces
change
in variable
1
2
3
Change
detected
by receptor
Input:
Information sent
along afferent
pathway to
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Response of effector feeds
back to influence
magnitude of stimulus &
returns variable to
homeostasis
Variable (In homeostasis)
Control
center
4
Output:
Information sent along
efferent pathway to
Homeostatic Control Mechanisms
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22. Regulatory Systems of Homeostasis
The nervous system and the endocrine
system are the two controlling bodies of
homeostasis
1. The Nervous Regulatory Mechanism
The nerves system is composed of three
major components the sensory portion, the
integrative portion and the motor portion.
The sensory receptor detects any change in
the body (BGC, BT, ABP, pain etc.) and
send impulse to the brain, spinal cord
(CNS).
The CNS associate the information store
some, generate thought and send
appropriate response to the effecter organs
(muscle + glands) through the motor
system.
Effector cell
NTs
R
Nerve Impulse
Hormone
Receptor
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23. Regulatory Systems of Homeostasis cont’d….
2. The Hormonal Regulatory Mechanism
Hormones are chemical messengers secreted by endocrine
glands, and transported in blood to the target gland (Organs).
Examples:
PTH act on the kidney, bone, and intestine = [Ca2+]
Aldosterone to the kidney [Na+]
ADH controls water electrolyte balance
An organism is said to be in homeostasis when its internal
environment contains an optimum amount of nutrients, gases,
electrolytes, water, hormones, enzymes and temperature.
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24. Blood Glucose Homeostasis
Normal BGC
70-110 mg/dl
4. Brain
All neurons
Feeding center
5. Hormones
Hyperglycemic hormones
Hypoglycemic hormones
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29. Disturbances of homeostasis
Deviations from normal ranges = PATHOLOGY
Hypo/ Hyperthermia ….. ↓or↑ Temperature
Hypo/ Hypercapnea ….. ↓or↑ PCO2
Acidosis/Alkalosis ….. ↓or↑ PH
Hypoxia/ Hyperoxia …. ↓or↑ PO2
Hypo/ Hypercalcemia …. ↓or↑ Ca 2+
Hypo/ Hyperglycemia … ↓or↑ Glucose
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30. Homeostatic control systems…
Depending on the site of regulation process
homeostatic controls may be classified in to;
1. Intrinsic controls
•Inherent in an organ
•The changes are automatically regulated by the
organ
Examples
• Reduction of 02 makes tissue release dilators
• Vascular auto regulation in exercising skeletal
muscle
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31. 2. Extrinsic controls
External stimuli initiate the regulation process
The most common type of controls
Nervous or endocrine system
The control mechanism initiated outside the organ & alter
the organ activities via coordinators
Maintain most of the factors in the internal environment.
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32. Homeostatic control systems…
Depending on the type/characteristics of
response homeostatic control may be;
I. Feedback control
Change in the controlled variable brings a corrective
response.
The regulatory processes established after the change
is developed
II. Feed-forward control
Anticipation of a change in the controlled variable
brings an anticipatory response.
The regulatory processes established before the
change is developed
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33. Feedback control mechanisms
There are two types of feed back mechanisms:
The Negative Feedback Mechanism (NFM)
The Positive Feedback Mechanism (PFM)
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34. Negative Feedback Mechanism (NFM)
It works by producing an effect which opposes the
previous condition
The NFM is a mechanism that opposes or counter acts the
deviation of a controlled variable from its normal value
(range/average).
Nature of Most Control Systems
For example: If the PCO2 is increased in the blood,
the negative feedback mechanism stimulates pulmonary ventilation
rate, which has an effect on decreasing PCO2 in blood to normal.
Most homeostatic values of the body are controlled by
NFM.
Control of ABP
Control of BGL
Control of BT
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36. The Positive Feedback Mechanism (PFM)
It works by producing an effect which enhances or repeats
the same action like that of the starting stimulus.
The PFM also called Viscous Circle.
Most of the action of this mechanism disturbs the internal
environment and cause disease & death.
Fore example, if a person suffers from a heart attack that
damages the heart function, then the heart pumps less
amount of blood to the tissues including the heart muscle
and brain.
If the heart muscle does not get sufficient nutrients and
O2, the activity of the heart becomes weaker and weaker
and the weaker the heart the lesser blood is pumped and
then death may occur.
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37. The Positive Feedback Mechanism cont’d…
Examples of the PFM
Blood clotting is an example of a very valuable use of
PFM.
Generation and propagation of the action potential.
Stimulated nerve fiber opening of Na+ channels
entry of few Na+ stimulates the opening of more and
more Na+ channels.
Labor during child birth, uterine contraction is enhanced as
the head of the baby stretches the cervix.
LH-surge
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40. Feed-forward
In physiology, feed-forward control is exemplified by the
normal anticipatory regulation of heartbeat in advance
of actual physical exertion.
Feed-forward control can be likened to learned
anticipatory responses to known stimulus.
Feedback regulation of the heartbeat provides further
adaptiveness to the running eventualities of physical
exertion.
Some activities needed be rapid that no enough time for
the brain to bring change after actual change occurred.
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41. Feed-forward…
The brain anticipates the change that will be developed.
Help for adaptation of the organ where correction will
be occurred
Correction is by anticipation
Example
- HR and RR before actual exercise
- Digestive juice before food inter into GIT
Used to adapt and rapid rate of response to the
change
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42. Levels of organization in the body
1. Chemical level
2. Organelle level
3. Cellular level
4. Tissue level
5. Organ level
6. System level
7. Organism level
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44. Cellular characteristics and structure
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The different substances that make up the cell are
collectively called protoplasm
Protoplasm is composed mainly of five basic substances:
Water ,
Electrolytes
Proteins
Lipids &
Carbohydrates
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45. 1.Chemical
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Includes all chemical substances necessary for life.
a. Atoms:
* Smallest chemicals such as; H, O, C, N
* Minerals- Ca, P, K, S, Na, Cl
* Trace element - Fe, I, Cu, Zn
b. Molecules:
* Collection of atoms or small molecules
E.g. H2O, CO2 , PO4 , NaCl & HCl
Biomolecules = carbohydrates, lipids, proteins, &
nucleic acids.
46. 1. Carbohydrates
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Carbohydrates- have little structural function in the cell except as
parts of glycoprotein molecules, but they play a major role in
nutrition of the cell
Composed of C, H2, & O2 atoms.
E.g. Glucose (C6H12O6 )
Combined with other biomolecules. Used for:
Structure & source of Energy for cells.
Amount usually averages about 1% their total mass, but increases to
as much as 3% in muscle cells &,
Occasionally, 6% in liver cells
Includes:
- Monosaccharide, Disaccharide, Polysaccharide
47. 2. Lipids
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Lipids- several types that are grouped together because of
their common property of being soluble in fat solvents.
Important lipids are phospholipids & cholesterol, which
together constitute about 2 % of the total cell mass.
Significance of phospholipids & cholesterol is that they
are mainly insoluble in water
Used to form the cell membrane & intracellular membrane
barriers that separate the different cell compartments
48. 2. Lipids…
48
‣ In addition to phospholipids & cholesterol, some
cells contain large quantities of triglycerides, also called
neutral fat.
‣ In the fat cells, triglycerides often account for
as much as 95% of the cell mass.
‣ The fat stored in these cells represents the body’s main
storehouse of energy-giving nutrients that can later be used to
provide energy wherever in the body it is needed
‣ About 40% of the dry mass of a typical cell.
‣ Composed largely of C & H2.
‣ Used for:
Energy storage, structural components & chemical messengers
Includes:
- Triglyceride, Fatty acids, Steroids
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49. 3. Proteins
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About 50 - 60% of the dry mass of a typical cell
Subunit is the amino acids
Two functional categories :
Structural &
Functional
50. 4. Nucleic Acids
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Biological molecules essential for life, and include:
DNA (deoxyribonucleic acid) and
RNA (ribonucleic acid)
Function in encoding, transmitting and expressing
genetic information.
51. Electrolytes
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Ions-Important ions in the cell include potassium,
magnesium, phosphate, sulfate, bicarbonate, and smaller
quantities of sodium, chloride, and calcium.
The ions provide inorganic chemicals for cellular reactions
and also are necessary for operation of some of the
cellular control mechanisms.
For instance, ions acting at the cell membrane are required
for transmission of electrochemical impulses in nerve &
muscle fibers
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52. Water
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Water. The principal fluid medium of the cell
which is present in most cells, except for fat cells, in a
conc. of 70 to 85 %.
Many cellular chemicals are dissolved in water.
Others are suspended in water as solid particulates.
Chemical reactions take place among the dissolved
chemicals or at the surfaces of the suspended particles or
membranes
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53. Embedded within the cytoplasm
Highly organized structures that perform specialized
functions within the cell
On average, nearly half of the total cell volume is occupied
by two categories of organelles—membranous organelles &
nonmembranous organelles
Machineries of the given cell
Combination of biological macromolecules.
Nearly all human cells contain five main types of
membranous organelle
These include
the endoplasmic reticulum,
Golgi complex,
lysosomes, peroxisomes, and mitochondria.
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II. Organelle
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54. Cellular organelles
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Membranous organelles are like intracellular “specialty
shops.”
Each is a separate internal compartment that contains a
specific set of chemicals for carrying out a particular cellular
function.
This compartmentalization permits chemical activities that
would not be compatible with one another to occur
simultaneously within the cell
For example, enzymes that destroy unwanted proteins operate
within the protective confines of the lysosomes without the risk
of destroying essential cell proteins.
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55. The nucleus
The nucleus is the control center for the cells.
It contains the genes, which are units of heredity.
Chemically each gene consists of highly compressed DNA,
the double strand genetic code that stores and transmits
genetic material, & also coordinates protein synthesis in
ribosomes- organelles of protein synthesis in the form of
chromosomes
Genes Control Cellular activity by determining the type
of proteins, enzymes, and other substances that are made by
the cell.
The nucleus is also the site of RNA Synthesis.
There are three kinds of RNA
Messenger RNA (mRNA), which carries the instruction from
DNA for protein synthesis to the cytoplasm
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56. The Nucleus
Ribosomal RNA (rRNA), which moves to the cytoplasm where it
becomes the site of protein synthesis
Transfer RNA (tRNA), serves as an amino acid transporter system
within the cell for protein synthesis.
Transcription phase of protein synthesis undertake in the
nucleus.
Following transcription, the mRNA ( single strand
template of protein synthesis) leaves the nucleus and
travels to the cell's ribosomes, where translation occurs.
In summary, the flow of genetic information in the cell
is: DNA → RNA induces to facilitate protein
transcription in nucleus →complex moves out of
nucleus → protein translation in ribosomes
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57. Are the sites of protein synthesis in the cell
Small particles composed of Ribosomal RNA &
proteins
Found in two forms:
Attached to the wall of ER or
As free ribosomes.
Free Ribosomes are found in two forms
-Scattered in the cytoplasm &
-Clustered (aggregated) to form functional
units called polyribosomes
Ribosomes
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58. Endoplasmic Reticulum (ER)
It is an extensive membranous structure that connects
various parts of the inner cell.
ER is also connected with the Nuclear Membrane.
There are two types of ER:
Rough ER &
Smooth ER.
The function of rER is to Segregate/isolate proteins
that are being exported from the cell.
rER is the site of protein synthesis
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59. Smooth Endoplasmic Reticulum (sER)
The sER is free of ribosome.
Function of sER varies in different cells.
The Sarcoplasmic Reticulum of skeletal & cardiac muscle cells are
forms of sER.
Calcium ions needed for muscle contraction are stored & released
from the sarcoplasmic reticulum of muscle cells.
In the Liver, the sER is involved in glycogen storage & drug
metabolism.
ER can synthesize a group of drugs metabolizing enzymes called
Microsomal System.
Function of sER:-
1. Glycogen storage
2. Calcium storage
3. Lipid biosynthesis
4. Drug metabolism (Detoxification) Endoplasmic reticulum (rER and sER)
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60. Golgi Complex
The Golgi complex consists of
flattened membranous saccules &
cisterns that communicate with the
ER & acts as a receptacle/container
for hormones and others substances
that the ER produces.
It then modifies and packages these
substances into secretary granules.
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62. Mitochondria-power house
It is called “power house of the
cell” or “power plants-factory”
because many of the reactions that
produce energy (energy rich
compound ATP which is required for
various cellular activities.) take place
in mitochondria.
The mitochondria require O2 to
produce energy (ATP) from food stuffs.
Lysosomes
• Membraneous structures in the cytoplasm that contains aggregates
of enzymes. Well developed in macrophages.
Function:
• Degrade old dead cells and phagocytosis of microorganisms
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63. Peroxisomes፡-
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Produce & decompose hydrogen peroxide (H2O2) in
the process of degrading potentially toxic molecules
(peroxi refers to “hydrogen peroxide”).
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64. Cellular organelles
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Nonmembranous Organelles- not surrounded by
membrane & thus are in direct contact with the cytosol
They include
Chromosomes,
Nucleoli,
Ribosomes,
Microtubules,
Microfilaments and centrioles.
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65. III. The Cell theory
Is the idea that all organisms are composed of cells.
In its modern form, the cell theory includes the ff
principles:
1. All organisms are composed of one or more cells
2. Cells are the smallest living things
3. Evolution of life:
. Prokaryotes (single-celled animals with no nucleus,
e.g. bacteria) evolved 3.5 billion years ago.
. Eukaryotes (nucleated single-celled animals),
evolved 1.5 billion years ago
4. Cells arise only by division of a previously existing cell
5. Cells are constructed of the same basic elements and share the
same basic materials and biosynthetic machinery, but differ by
shapes and molecular structures
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66. Cell…
The smallest, structural & functional unit of life.
It is the smallest living unit of the human body.
Contain basic characteristics of a given organism.
Numerous in number & estimates being 75 - 100 trillion cells
in the average adult human.
The red blood cells, numbering 25 trillion in each human
being, transport oxygen from the lungs to the tissues.
There are many different types of cells in the body including:
1. Epithelial cell
2. Connective tissue cell
3. Muscle cell
4. Nervous tissue cell
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67. Generalized cell
Components of cells
Trillions of cells in a human body are classified into about 200
types based on specific variations in structure & function.
Despite their diverse structural & functional specializations,
however, different cells share many features in common.
Most cells have three major subdivisions:
The plasma membrane, which encloses the cells
The nucleus, which contains the cell’s genetic material &
The cytoplasm, the portion of the cell’s interior not occupied
by the nucleus
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70. The Cytoskeletal System
Microfilament &
microtubules
They are long, rigid thread like
structures dispersed through
out the cytoplasm.
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71. Functions of Cytoskeletal System
1) Maintain shape of the cells.
E.g. Axon
2) Serve as a transport system for the movement of
compounds and organelles within the cell.
3) Construct the mitotic spindle. E.g. Centriols
4) Provide for the support & movement of cilia & flagella
5) Cell to cell contact: to fasten cell membranes together
6) Essential for appropriate leukocyte migration.
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72. Communication Function of the Cell
How do cells get information?
A very few specialized cells have “ears” or “eyes” sensitive to
pressure or light.
Almost all cells, sense their environment primarily by detecting
chemical or electrical signals probably by employing surface
proteins (receptors)
Mechanisms of signaling are: autocrine, paracrine, endocrine
and synaptic. The major mechanisms are neural & endocrine.
Embedded within the plasma membrane, i.e. all cells can receive
& process information.
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73. Intercellular signaling cont’d…
Intercellular Communication Classifications
Endocrine signals
Produced by endocrine cells
Travel through the blood to reach all parts of the body.
Paracrine signals
Target only cells in the surrounding area of the releasing cell.
E.g. Neurotransmitters
Autocrine signals
Affect only cells that are of the same cell type as the emitting
cell.
An example for autocrine signals is found in immune cells
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75. Intracellular Connections and Communications
Most cells (epithelial, muscle, some nerve) cells are
tightly joined to form a close functional unit.
Points of contact between two adjacent plasma
membranes are called cell junctions. There are 3- types of
cell junction:
1. Tight (occluding) junctions
form fluid-tight seals between cells
2. Desmosomes (anchoring junctions)
fasten cells together
3. Gap (communicating) junctions permit electrical
signals to pass.
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77. Tight Junctions (Occludens)
Are tightly stitched seams between cells.
Prevent movement of material between the cell
Are common among epithelial cells that line the stomach, intestine, and
urinary bladder.
where materials are required to pass through cells (rather than intercellular
spaces) to penetrate the bloodstream.
Provide the interface between masses of cells and a cavity or space (a lumen)
apical structures (Fig. below) that tie cells together and endow them with
strength and stability.
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78. Adherens Junctions
Provide strong mechanical attachments between adjacent
cells
They hold cardiac muscle cells tightly together as the
heart expands and contracts
They hold epithelial cells together
Some adherens junctions are present in narrow bands
connecting adjacent cells
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79. Gap Junctions
Gap junctions are intercellular channels
some 1.5–2 nm in diameter
Formed by two connecting trans-
membrane protein rings (connexins), They
are cylinders constructed from 6 copies of
Transmembrane proteins called connexins
facilitate;
free passage of ions and small molecules
including water and small solutes(up to a
molecular weight of about 1000 Daltons)
between the cells
Permit electrical or chemical signals to pass
from cell to cell
It allows the rapid spread of AP from one cell
to the next in the nervous system & muscle.
Each connection in membrane of one cell
lines up with a connection in the
membrane of neighboring cell
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81. Desmosomes
Intercellular rivets creating tight bonds b/n cells, but allow fluids to
pass through intercellular spaces
Inside the plasma membrane, a desmosome bears a disk-shaped
structure from which protein fibers extend into the cytoplasm.
Act like spot welds to hold together tissues that undergo considerable
stress (such as skin or heart muscle).
They are common in epithelia (e.g., the skin).
Desmosomes are attached to intermediate filaments of keratin in the
cytoplasm
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82. FIGURE Desmosome. Desmosomes are adhering junctions
that spot-rivet cells, anchoring them together in tissues subject to
considerable stretching.
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83. IV The Tissue
Tissues are groups of cells, and the
surrounding environment, which
work together to produce a specific
function.
There are only four types of tissues
in the body:
1. Epithelial tissue
2. Connective tissue
3. Muscle tissue
4. Nervous tissue
This is an illustration of muscle
tissue. The muscle cells and
surrounding matrix make up the
structure that works in concert
with the brain to produce
movement in the body.
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84. VI. The Organ
Organs are structures that are made of two or
more different types of tissues.
They have specific functions and a defined shape.
Head, Heart , Stomach, Spinal cord…
The heart is an example of an organ.
It is made of muscle, as well as
connective and nervous tissue.
The tissues work in concert to move
blood through the body.
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85. VI. System
Consists of Related organs that have common function.
Lung, trachea, chest wall, bronchioles, alveoli, diaphragm form
respiratory system.
Brian, spinal cord, special senses, nerve form nervous system.
Mouth, esophagus, stomach, small intestine etc. form digestive
system etc.
There are Eleven Organ systems in the body:
1. The Integumentary System
2. The Skeletal System
3. Muscular System
4. Nervous System
5. Endocrine System
6. Cardiovascular System
7. Lymphatic & Immune System
8. Respiratory System
9. Digestive System
10. Urinary System
11. Reproductive System
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89. VII. Organism
The highest level of organization
Coordinated interaction activities in each of the levels
that enable us to exist
We are more than sum of parts
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90. Structural levels of organization of human body summary
Muscle cells
Nerve cells
Cells: 4 types Epithelial cells
Cells in the connective tissues
Muscle tissue
Tissues 4 types Nerve tissue
Epithelial tissue
connective tissues
Organs: Example: Heart, lungs
Organ system: Example: Respiratory system, CVS
Organism: Human organism
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Physiology is the study of study of the mechanisms and functions within living systems from the ionic level up to the whole animal. To maintain healthy function, all of these aspects must operate optimally, including adapting to changes in the internal or external environment. This course will develop your understanding from the ionic level through to the integration of whole systems that are required to sustain life. This will provide a foundation for understanding how often subtle changes can underlie disease, how we are able to treat disease and how future generations of scientists may develop improved and new treatments
Osmolality:- (OZ-mo-LAL-ih-tee) The molar concentration of dissolved particles in 1 kg of water
Frank-Starling mechanism in the heart
Organelles are distinct, highly organized structures that perform specialized functions within the cell. On average, nearly half of the total cell volume is occupied by two categories of organelles—membranous organelles and nonmembranous organelles. Each membranous organelle is a separate compartment within the cell that is enclosed by a membrane similar to the plasma membrane. Thus, the contents of a membranous Nearly all human cells contain five main types of membranous organelle. Membranous organelles are like intracellular “specialty shops.” Each is a separate internal compartment that contains a specific set of chemicals for carrying out a particular cellular function. This compartmentalization permits chemical activities that would not be compatible with one another to occur simultaneously within the cell. For example, enzymes that destroy unwanted proteins operate within the protective confines of the lysosomes without the risk of destroying essential cell proteins. .
The nucleus houses the cell’s genetic material, deoxyribonucleic acid (DNA), which, along with associated nuclear proteins, is organized into chromosomes. Each chromosome consists of a different DNA molecule that contains a unique set of genes. Body cells contain 46 chromosomes that can be sorted into 23 pairs on the basis of their distinguishing features. DNA has two important functions:
1. Serving as a genetic blueprint during cell replication. Through this role, DNA ensures that the cell produces additional cells just like itself, thus continuing the identical type of cell line within the body. Furthermore, in the reproductive cells (eggs and sperm), the DNA blueprint passes on genetic characteristics to future generations. 2. Directing protein synthesis. DNA provides codes, or “instructions,” for directing synthesis of specific structural and enzymatic proteins within the cell. Proteins are the main structural component of cells, and enzymes govern the rate of all chemical reactions in the body. By specifying the kinds and amounts of proteins that are produced, the nucleus indirectly governs most cell activities and serves as the cell’s control centere
Like lysosomes, Peroxisomes are membrane-enclosed sacs containing enzymes, but unlike lysosomes, which contain hydrolytic enzymes, peroxisomes house several powerful oxidative enzymes and contain most of the cell’s catalase. Oxidative enzymes, as the name implies, use oxygen (O2), in this case to strip hydrogen from certain organic molecules. This reaction helps detoxify various wastes produced within the cell or foreign toxic compounds that have entered the cell, such as alcohol consumed in beverages. The major product generated in the peroxisome, H2O2, is formed by molecular oxygen and the hydrogen atoms stripped from the toxic molecule. H2O2 is potentially destructive if allowed to accumulate or escape from the confines of the peroxisome. However, peroxisomes also contain an abundance of catalase, an enzyme that decomposes potent H2O2 into harmless H2O and O2. This latter reaction is an important safety mechanism that destroys the potentially deadly H2O2 at its site of production, thereby preventing its possible devastating escape into the cytosol.
The nonmembranous organelles are not surrounded by membrane and thus are in direct contact with the cytosol. They include ribosomes, proteasomes, vaults, and centrioles. Like membranous organelles, nonmembranous organelles are organized structures that carry out specific functions within the cell. Organelles are similar in all cells, although some variations occur depending on the specialized capabilities of each cell type. Just as each organ plays a role essential for survival of the whole body, each organelle performs a specialized activity necessary for survival of the whole cell A proteasome, a nonmembranous organelle, is a protein degradation machine: It is a cylinder shaped complex about the size of a ribosomal subunit that contains multiple protein-digesting enzymes that break down ubiquinated proteins into recyclable building blocks
The trillions of cells in a human body are classified into about 200 types based on specific variations in structure and function. Despite their diverse structural and functional specializations, however, different cells share many features. Most cells have three major subdivisions: the plasma membrane, which encloses the cells; the nucleus, which contains the cell’s genetic material; and the cytoplasm, the portion of the cell’s interior not occupied by the nucleus
