2. Living processes in unicellular
organisms
• Unicellular organisms (organisms which consist a
single cell).
• They are structurally simple, but able to perform
all vital functions and living processes within a
cell.
• They can feed, respire, excrete, move, sensitive to
external and internal conditions (respond to
stimuli), able to reproduce and grow.
3. • they does not have any systems, so the survival
depends largely on their structure and cellular
components.
• Example of unicellular organisms: protozoa
(Amoeba sp and Paramecium sp)
4. Amoeba sp
Habitat
• live in freshwater lakes, ponds and damp soil
• Most are free living, but some are parasitic.
General characteristics
• Enclosed by a plasma membrane
• Changes its shape constantly as it meets obstacles
and responds to stimuli.
• Ectoplasm (the gel-like outer part of the cytoplasm),
endoplasm (the inner part of the cytoplasm)
• Moves and feeds by using pseudopodia.
5. Living processes
1. Locomotion
• Moves by cytoplasmic projection (extending
pseudopodia or ‘false feet’ and anchoring the
tips to the ground)
• Followed by the flow of cytoplasm into the
pseudopodia.
• This form of locomotion is known as ameboid
movement.
6. 2. Feeding
• Feed on microscopic organisms such as bacteria
and diatoms.
• Engulfs food by phagocytosis.
• Nutrition in Amoeba sp:
a) Amoeba sp approaches the food particles.
b) Two pseudopodia extend out and enclose the
food particles.
c) The food particles are packaged in a food
vacuole, which fuses with a lysosome
containing hydrolytic enzymes called lysozyme.
7. (d) The food particles are digested by the lysozyme.
The resulting nutrients diffuse into the cytoplasm
and are assimilated.
(e) Undigested material is left behind when the
Amoeba sp moves away.
3. Respiration
• Exchange of oxygen and carbon dioxide occurs
through the plasma membrane by diffusion.
8. 4. Excretion
• Waste products such as carbon dioxide and
ammonia are eliminated by diffusion.
• The contractile vacuole is involved in
osmoregulation.
• As Amoeba sp lives in freshwater environments ,
water diffuses into the cell and fills the contractile
vacuole.
• When the vacuole is filled to its maximum size, it
contracts to expel its contents from time to time.
9. 5. Responses to stimuli
• reacts by retreating from adverse stimuli such as
bright light and acidic solutions.
• Favorable stimuli such as contact with
food, cause it to move toward the stimuli.
6. Reproduction
• Reproduces asexually by binary fission and by
forming spores.
• When food is abundant, Amoeba sp reproduces
by binary fission.
• When food is scarce and the condition is
dry, Amoeba sp forms spores.
10. Binary fission in Amoeba sp
• Amoeba sp divides after it has grown to a certain
size.
• The pseudopodia are pulled in and the nucleus
divides.
• The cytoplasm begin to divide when the nucleus
has split.
• Two daughter amoebae are formed.
7. Growth
• Grow by synthesizing new cytoplasm.
11. Paramecium sp
Habitat
• Found abundantly in freshwater ponds rich in
decaying organic matter.
General characteristics
• The surface is covered by numerous rows of cilia
(short hair-like outgrowths which cover the entire
outer surface of the Paramecium sp).
• cilia are involved in locomotion and feeding.
12. Living processes
1. Locomotion
• Moves by means of the rhythmic beating of the
cilia.
• This action enable the Paramecium sp to move
forward while rotating and spiralling along its
axis.
2. Feeding
• Feed on microscopic organisms.
13. • Nutrition in Paramecium sp:
a) the rhythmic beating of cilia along a mouth-like
opening (oral groove) sweeps water and
suspended food particles into the cytostome.
b) In the cytostome, food vacuoles containing the
food particles are formed.
c) The food particles in the food vacuoles are
digested by hydrolytic enzymes from the
cytoplasm.
d) Nutrients from the digested food then dissolve
and diffuse into the cytoplasm and are used to
generate energy.
14. e) The undigested contents are released through
the anal pore.
3. Respiration
• Gaseous exchange occurs by diffusion through
the entire plasma membrane.
15. 4. Excretion
• Waste products are expelled from the cell by
diffusion.
• Control of water balance in the cell
(osmoregulation) is aided by two contractile
vacuoles (one at the anterior and the other at
the posterior end).
• This is necessary because Paramecium sp
constantly takes in water from the hypotonic
environment by osmosis.
• Contractile vacuoles periodically expand, filling
with water, and then contract to expel their
contents to the exterior of the cell.
16. 5. Responses to stimuli
• Has cilia which function as sensory structures.
• It is sensitive to chemicals, oxygen, carbon
dioxide, pH and physical stimuli such as light,
contact and temperature.
• Moves in the opposite direction when it comes
into contact with adverse stimuli.
6. Reproduction
• Reproduce asexually as well as sexually.
17. • Has two nuclei. macronucleus control cellular
metabolism of the cell and for asexual
reproduction (binary fission, occur in favorable
environment). micronucleus is required for
sexual reproduction (conjugation, occur in
unfavorable environment).
• Binary fission in Paramecium sp:
Macronucleus and micronucleus divide.
The cytoplasm divides when the nuclei have
split.
Two daughter Paramecium sp are formed.
18. 7. Growth
• Grow to a certain size by synthesizing new
cytoplasm.
19. Cell specialisation in multicellular
organisms
• Multicellular organisms (organisms that consist
more than one cell).
• Cell specialisation (a process of change and
adaptation that a cell undergoes to give it special
structures and specific functions).
• Human and other multicellular organisms begin
life as a single cell known as a zygote (result of
fertilisation between an ovum and a sperm.
20. • Then, zygote divides into two identical cells
divide to become four cells, and so on until it
forms a ball of cells (embryo).
• These cells grow, change shape and adapt
themselves to carry out specific functions.
• They differentiate and become specialised in
order to perform specific tasks more efficiently.
• The different levels of cell organisation as below:
A group of cells (similar in structure, perform a
specialised function) tissue.
Different types of tissues organs.
21. Several organs system.
All systems multicellular organism.
• Without cell specialisation, organism will not be
able to survive itself, given the complexity and
the millions of cells found in its body.
• Organisation into cells, tissues, organs and
systems is essential to multicellular organisms
because:
a group of cells or tissues are able to carry out a
specific function more efficiently compared to a
single cell.
22. the division of labour among cells enables the
organisms to carry out the various tasks and
functions in an orderly and systematic manner.
this enables them to achieve a higher growth
rate.
organism are able to adapt and survive in diverse
habitats and environments.
all living processes can be carried out more
efficiently.
23. A few types of human cells
1. Nerve cells
• Have long, thin fibres called axons which
conduct nerve impulses throughout the body.
2. Muscle cells
• Are usually long with multiple nuclei and
contain protein fibres. These fibres can contract
to produce movement.
24. 3. Red blood cells
• Are shaped like a biconcave disc and lack a
nucleus. This increase their efficiency in
transporting oxygen.
4. White blood cells
• Can change their shape easily to move through
the walls of blood vessels and migrate to the sites
of injuries.
25. 5. Sperm cells
• Have long tails and a high density of
mitochondria which allow them to swim
towards the ovum.
• The nucleus contains one set of chromosomes
from the male parent.
6. Epithelial cells with simple glands
• Found in the intestines.
• Function: secrete mucus
• The epithelial layer is highly folded with the
secretory cells arranged compactly to increase
the surface area for mucus secretion.
26. tissues
• Four major types of tissues in animals:
1. Epithelial tissues
Consist of one or more layers of cells.
The cells of an epithelium are tightly
interconnected, with little space between them.
They form a continuous layer over body surfaces
(skin and mouth area), inner lining of cavities
(digestive tract and lungs), and also form glands
(exocrine and endocrine glands).
27. Functions:
a) Epithelial cells carry out functions associated
with protection, secretion and absorption.
b) At surface of the skin, act as a protective barrier
against infections, mechanical injuries,
chemicals, dehydration and regulate body
temperature.
28. c) The epithelial cells (alveoli of the lungs and the
walls of blood capillaries) are thin, flattened and
arranged in a single layer (allow the exchange of
gases between the alveoli and the blood in the
capillaries to take place efficiently).
d) In the lining of the small intestine, absorb
nutrients after digestion is completed.
e) Undergo modification to form mucus-secreting
goblet cells which secrete mucus into the
digestive tract.
29. f) Certain epithelial tissues are modified to form
glands in the skin (sweat glands and
sebaceous/oil-secreting glands).
g) The epithelial tissues that lines the trachea
consist of elongated cells with hair-like
projections called cilia. They secrete mucus (trap
dust particles while the cilia sweep the impurities
away from the lungs).
30. 2. Muscle tissues
The most abundant tissues in most animals.
Composed of long cells called muscle fibres.
Three types of muscle tissues:
a) Smooth muscles (along the walls of the
digestive tract, blood vessels, bladder and
reproductive tract).
b) Skeletal muscles (attached to the bones of the
skeletal).
c) Cardiac muscles (form the contractile wall of the
heart).
31. Function:
a) Smooth muscles
• responsible for the involuntary actions of the
body. Example: when the smooth muscles of
the intestine contract, food is moved along the
digestive tract.
• Responsible for the churning action of the
stomach and the constriction of arteries.
• Contract more slowly than skeletal muscles but
remain contracted for a longer period of time.
32. b) Skeletal muscles
• Responsible for the voluntary movements of the
body. Contractions of skeletal muscles produce
movements of various body parts.
c) Cardiac muscles
• Contract to pump blood to all parts of the body.
Contractions are involuntary.
33. 3. Nerve tissues
Composed of neurones, or nerve cells.
Each neurone consists of a cell body and nerve
fibres called dendrites and axons.
Three types of neurones:
a) Afferent neurones
b) Efferent neurones
c) Interneurones
34. Function:
a) Neurones are specialised to transmit signals
called nerve impulses over long distances.
b) Nerve tissues control and coordinate all
activities of the body.
35. 4. Connective tissues
Consist of various types of cells and fibres
separated by an extracellular matrix.
The connective tissues which underlines
epithelial tissues consists of a network of
collagen, capillaries and spaces filled with fluid.
Examples: tendons, ligaments, cartilage, bones,
blood, lymph and adipose tissue.
Connective tissues, with the exception of blood
and lymph, are interwoven with fibrous strands
called collagen.
36. tendons and ligaments: formed when the
collagen fibres are densely packed.
cartilage: strong yet flexible connective tissues.
Bones: consist of cells embedded in a matrix of
collagen hardened by mineral deposits such as
calcium. This combination makes the bones
harder than cartilage.
37. Blood: consists of red and white blood cells and
cell fragments called platelets, suspended in a
fluid called blood plasma. Blood cells are
manufactured in the bone marrow, located at the
ends of long bones.
Lymph: consists mostly of fluid which leaks out of
blood capillaries.
Adipose tissues (formed by fat cells): tightly
packed. Found in the dermis of the skin.
38. Functions:
a) Bind structures together, provide support and
protection to other tissues.
b) Tendon: attach muscles to bones.
c) Ligaments: attach bones to bones.
d) Cartilage: provides support to nose, ears, and
the ends of bones at joints. Also forms discs
between the vertebrae. This enables them to act
as cushions to absorb pressure.
e) Bones: provide protection to organs in the body
and supports the body.
39. f) blood: has regulating, transporting and
protective functions. transports nutrients and
oxygen to cells and removes carbon dioxide and
waste products from the cells. Distribute heat
throughout the body and contains regulatory
substances (hormones and enzymes). Red blood
cells transport oxygen, white blood cells assist in
fighting infections, platelets aid in blood clotting.
g) Adipose tissues: store energy and insulate the
body.
40. Organs
• Formed by two or more types of tissues (not
individual tissues) working together to perform
particular functions.
• Examples: heart, skin, lungs, kidneys, eyes and
ears.
• The heart consists of cardiac muscle, connective
tissue, nerve tissue and epithelial tissues. These
tissues work together to pump blood to all parts
of the body.
41. Skin
• Covers the entire body, and acts as a barrier
against in infection, physical trauma and water
loss.
• The largest organ of the body.
• Is organ because it consists of various types of
tissues combined together to perform specific
functions.
• Divided into two main layers (epidermis and
dermis).
42. • Epidermis: the outermost, thinner layer of the
skin. Mostly made up of dead epithelial cells
which continually slough off.
epithelial cells at the basal layer of the
epidermis undergo continuous cell division.
43. • Dermis: composed of connective tissue, nerve
tissue, epithelial tissue and muscle tissue.
Connective tissue contain elastic fibres and
collagen fibres. Elastic fibres give elasticity to the
skin, allow the skin to return to its original shape
after being stretched.
Various nerve endings are scattered all over the
dermis and epidermis. These nerve endings are
receptors for pressure, temperature, touch and
pain. They detect various stimuli and transmit
nerve impulses to the nervous system.
44. Epithelial cells: form glands such as hair follicles
(produce hair), sweat glands (secrete sweat), oil
glands (secrete sebum). Sebum is an oily
substance that lubricates the hair and the skin.
Smooth muscle (hair erector muscle) is attached
to the hair follicle. when contracted, it causes the
hair to stand on end.
45. systems
• Each system consists of several organs that
cooperate to carry out a living process (digestion
of food).
• 11 major systems in humans:
1. Nervous system
Major organs: brain, spinal cord, nerves
46. Main functions: detects stimuli, formulates
responses, transmits nerve impulses and
integrates the activities of systems. Controls
physiological processes in conjunction with the
endocrine system.
2. Skeletal system
Major organs: bones, cartilage, tendons,
ligaments
Major functions: supports the body, provides
sites for attachment of muscles, and protection
for internal organs.
47. 3. Circulatory system
Major organs: heart, blood vessels, blood
Main functions: delivers nutrients, respiratory
gases and hormones to body cells. Transports
waste products to excretory organs.
4. Digestive system
Major organs: mouth, pharynx, esophagus,
stomach, liver, pancreas, small and large
intestines, anus.
Main functions: ingests and digests food,
absorbs nutrients for use by the body and
eliminates undigested material.
48. 5. Respiratory system
Major organs: nose, trachea, lungs
Main functions: provides a surface area for gases
exchange between the blood and the external
environment. Allows oxygen intake and carbon
dioxide elimination.
6. Excretory system
Major organs: kidneys, ureters, urinary bladder,
urethra, skin, lungs.
Main functions: removes metabolic waste
products (urea and carbon dioxide). Regulates
the osmotic balance of the blood.
49. 7. Reproductive system
Major organs: male (testes, seminal vesicles,
penis), female (ovaries, Fallopian tubes, uterus,
cervix, vagina)
Main functions: male (produces sperms and male
hormones), female (produces ova, nurtures
developing foetuses, and produces female
hormones.
50. 8. Muscular system
Major organs: skeletal muscles, smooth muscles
and cardiac muscles
Main functions: contraction of muscles enables
body movements.
9. Integumentary system
Major organs: skin
Main functions: physically separates the body
from the external environment. Protects the
body against mechanical injuries, microbial
infection and dehydration.
51. 10. Endocrine system
Major organs: glands (pituitary, thyroid, adrenal
and pancreas) secrete hormones.
Main functions: coordinates body activities in
conjunction with the nervous system.
11. Lymphatic system
Major organs: lymph vessels, lymph nodes, bone
marrow, thymus.
Main functions: defends the body against
infections. Returns tissues fluid to the blood.
52. • An organ may belong to more than one system.
Example: pancreas secretes hormones and
pancreatic juice. Pancreas is a part of the
endocrine system and the digestive system.
• All systems combine to form a multicellular
organism.
53. Cell organisation in plants
• Plant cells also undergo cell specialisation.
• plant cells undergo differentiation and become
specialised in structure and function:
1. Mesophyll palisade cells
Consist of elongated, cylindrical cells, arranged
vertically and close to one another, situated just
below the upper epidermis. This allow as much
light as possible to reach the chloroplasts for
photosynthesis.
54. Contain a large number of chloroplasts for
maximum absorption of sunlight.
2. Xylem vessels
No cytoplasm, hence, water can pass freely.
The end walls of the cells are perforated, and the
cells form a continuous vessel or tube which
allows water and mineral salts to be transported
in the plant.
55. 3. Guard cells
Specialised epidermal cells at the lower
epidermis which are kidney-shaped when turgid.
Control the size of the stoma by changing their
shape.
4. Root hairs
Have a long extension which increases the
surface area for absorption of minerals and water
from the soil.
56. • 2 main types of tissues (meristematic tissues and
permanent tissues) form plant organs (leaves,
stems and roots).
1. Meristematic tissues
Consists of small cells which have thin walls,
large nuclei, dense cytoplasm and no vacuoles.
Comprise young and actively dividing cells which
have not undergone differentiation.
57. Apical meristems are located at the tips of roots
and the buds of shoots. The tissues undergo
mitotic cell division to increase the number of
cells for plant growth.
Lateral meristems/cambia are found in the
peripheral areas of stems and roots. They are
responsible for secondary growth which adds
girth to the plants.
58. 2. Permanent tissues
Consist of more mature cells that are either
undergoing differentiation or have already
undergone differentiation.
3 types of permanent tissues:
a) Epidermal tissue
Characteristics
i. Forms the epidermis (the outermost layer that
covers the stems, leaves and roots of young
plants). This tissues also covers the flowers,
fruits and seeds.
59. ii. The walls of epidermal cells which are exposed
to air are normally covered by a waxy,
waterproof coating called the cuticle.
iii. Most are flat and have large vacuoles.
Functions
i. The cuticle helps prevent the loss of excessive
water through evaporation, protects the plant
from mechanical injury and prevents invasion
by disease-causing microorganisms.
60. ii. In roots, some have long projections called root
hairs. These specialised structures increase the
surface area for absorption of water and
minerals.
iii. In leaves, the lower epidermis contains
specialised cells (guard cells) which surround the
stomata.
61. b) Ground tissue
Forms the bulk of a plant.
3 types of ground tissues:
1) Parenchyma tissue
Characteristics
i. Consists of thin-walled cells which are loosely
arranged with spaces between them.
ii. cells have a large vacuole.
iii. The least specialised cells and can be found in
all the organs of a plant.
62. Functions
i. Parenchyma cells store products of
photosynthesis (sugar and starch).
ii. The palisade mesophyll cells and spongy
mesophyll cells in leaves are specialised
parenchyma cells which contain chloroplasts
and carry out photosynthesis.
iii. Gives support and shape to plants.
63. 2) Collenchyma tissue
Characteristics
i. Consists of elongated, polygonal cells with
unevenly thickened cell walls (thickened by
cellulose and pectin. Strong and flexible).
Functions
i. an important source of support in herbaceous
plants, young stems, leaf stalks and petioles.
64. 3) Sclerenchyma tissue
Characteristics
i. Sclerenchyma cells are much more rigid than
collenchyma cells because they have cell walls
which are uniformly thickened by lignin.
ii. Most of the cells are dead at maturity.
Functions
i. Supports and strengthens the plant body and
provides protection to the plant.
65. c) Vascular tissue
Vascular tissues (are continuous throughout the
plant) are involved in the transport of substances
between the roots and shoots.
2 types of vascular tissues:
1) Xylem tissue
characteristics
i. Xylem consists of tracheids and xylem vessels.
these are long tubes joined together end to
end, stretching from the roots right up to the
shoots.
66. ii. The cell walls of the xylem are thickened with
lignin which prevents food substances from
entering the cells.
iii. Dies upon reaching maturity.
iv. When the cytoplasm disintegrates, a hollow tube
is left behind. This allows water and minerals to
flow easily through the xylem vessels.
67. Functions
i. Xylem conducts water and minerals from the
roots to the leaves.
ii. It provides support and mechanical strength to
the plant.
68. 2) Phloem tissue
Characteristics
i. Consists of parenchyma cells, sclereids, sieve
tubes and companion cells.
ii. The conducting cells of phloem are the sieve
tubes (have pores at both ends, called sieve
plates. Obtain nutrients and energy from the
adjacent companion cells).
Functions
i. Phloem transports organic nutrients
(carbohydrates and amino acids) downwards
from the leaves to storage organs and growing
parts of plants.
69. Organs and systems in plants
• Plant organs: leaves, stems, roots and flowers.
• Systems in plants are not specialised as those of
animals. Plants have fewer organs as compared
to animals.
70. • Flowering plants (angiosperms) consist of 2 main
systems:
1. Root system
Is the absorptive system of a plant.
The roots are highly branched to absorb water
and minerals from the soil and transport them to
the main vascular system (xylem).
the roots anchor the plant to the ground.
71. 2. Shoot system
Consists of organs (stems, leaves, buds, flowers
and fruits).
Stems and branches act as a support system for
the plant by holding the leaves in a position that
facilitate maximum absorption of sunlight during
photosynthesis. They also position the flowers
for pollination.
72. Leaves are made of ground tissue, epidermal
tissue, mesophyll tissue and vascular tissue.
They form the main photosynthetic system
(synthesises organic compounds required for
plant growth).
The products of photosynthesis are transported
via the vascular system (phloem) to other parts of
plants.
Reproductive system of plants consists of flowers
which produce fruits after fertilisation has taken
place.
73. The internal environment of
multicellular organisms
• Although multicellular organism lives in external
environment, the cells of its body live within
internal environment (consists of the interstitial
fluid and blood plasma).
• interstitial fluid fills the spaces between the cells
and constantly bathes the cells.
• Nutrients and waste substances are exchanged
between the interstitial fluid and the blood
plasma (contained in the blood capillaries).
74. The necessity for maintaining optimal
internal environment
• In order for cells of the body to function
optimally, the physical factors and the chemical
composition within the internal environment
must be maintained at relatively constant level
regardless of the conditions outside the cells.
• Physical factors: temperature, blood pressure,
osmotic.
• Chemical factors: salt and sugar contents, pH.
75. • Homeostasis is the maintenance of a relatively
constant internal environment for the optimal
functions of cells.
• In humans and animals, mechanism of
homeostasis maintain the physical factors and
chemical factors of the internal environment at
steady state with minimal fluctuations.
76. In homeostatic control mechanism, the change in
internal environment
detected
receptor
send message
control centre
processes information
effector
(bring about a counter response that reverse the
change back to original condition)
77. • in plants, the need for regulatory system is lesser
because:
a) Most plant cells are dead at functional maturity,
so chemical reactions do not take place in these
cells.
b) Plant cells are not bathed in fluid but surrounded
by air.
c) Plant cells do not lyse in hypotonic environment
because they have cell walls.
d) Water movement in plants is aided by natural
factors (transpirational pull).
78. The importance of regulating optimal
internal environment
• Ensure optimal cellular activities at times when
the external environment (temperature of
environment) changes.
• Enable organisms to live in a wider range of
habitats.
• Metabolic activities and physiological processes
can still continue even though the external
environment fluctuates substantially.
79. • Organisms can control the metabolic rate
according to their needs because any internal
fluctuations can be corrected through the
homeostatic control system.
• Ensure a more efficient and optimal metabolism
in the cell.
• A stable internal environment allows enzymes to
function at optimal rate.
80. The involvement of various system in
maintaining optimal internal
environment
• Physical factors/chemical factors of the internal
environment:
1. Body temperature
Systems involved
Integumentary system (skin and sweat glands).
Nervous system
Circulatory system
Muscular system
Endocrine system
81. Types of regulation
Regulate the balance of heat loss and heat gain
to maintain stable body temperature of 37oC.
When the temperature of the body rises above
the normal value,
Thermoreceptors in the skin detect the change in
temperature.
The nervous system conveys the information to
the hypothalamus.
Then, the information is conveyed to effectors.
82. The effectors involved are:
a) Sweat glands: secrete more sweat to cool the
body through evaporation.
b) Blood vessels: dilate to increase heat loss to the
environment.
c) Hair erector muscles: relax so as to flatten hair
to reduce insulation.
d) Thyroid gland: less stimulated, the secretion of
thyroxine is reduced and this result in a lower
basal metabolic rate.
83. Overall result: lowering of the body temperature
to the normal level.
On cold day, the opposite mechanism occur.
84. 2. Oxygen and carbon dioxide levels
Systems involved
Respiratory system
Circulatory system
Nervous system
Types of regulation
Regulate the concentration of oxygen and
carbon dioxide in the bloodstream.
85. circulatory system transports oxygen from the
lung to the cells. Carbon dioxide produced
during respiration diffuse into the bloodstream
and is transported back to the lungs.
The change in the concentration of oxygen and
carbon dioxide are detected by the nervous
system.
86. 3. Blood glucose level
Systems involved
Endocrine system (pancreas)
Circulatory system
Digestive system (liver)
Types of regulation
Regulate blood glucose level at a set point of 90
mg per 100 cm3.
87. Pancreas secrete insulin when the level of
glucose in the blood rises above the set point.
Circulatory system transport insulin to the liver.
Insulin stimulate liver cells to convert glucose
into glycogen. Blood glucose level drops.
When the glucose level falls below the set point,
pancreas secrete glucagon (promote the
breakdown of glycogen and the release of
glucose into the blood).
88. 4. Blood osmotic pressure
Systems involved
Nervous system
Endocrine system
Excretory system
Circulatory system
Types of regulation
Regulate the amount of water and dissolved
substances (mineral salts) in the tissue fluid and
blood.
89. 5. pH
Systems involved
Respiratory system
Circulatory system
Excretory system (kidneys)
Types of regulation
pH of blood and tissue fluid is maintained at a
value of 7.4 by regulating the concentration of
hydrogen ions (H+), hydroxyl ions (OH-) and
hydrogen carbonate ions (HCO3
-).
90. Appreciating the uniqueness of the
cell
• Cell: the basic unit of all living organisms and is
capable of functioning on its own.
• Cellular components of the cell are completely
dependent upon one another for the cell to
function at optimal level.
• The cell as a whole will not be able to function
properly if any of its cellular components loses its
ability to function normally. Optimal cellular
function is the result of cellular order within the
cell.
91. • Systems of organisms are able to function
efficiently because the cellular components of
cells work together and cooperate harmoniously
with each other.
• This ensure the survival of the organism.