1. Cell organisation

2. TISSUE
 Tissue can be classified into four types:
- epithelial tissue
- Muscle tissue
- Connective tissue
- Nerve tissue

4. 1. Epithelial tissue
 Consists of one or more layers of cells
 Are tightly interconnected and form a continuous layer
over body surfaces(skin&mouth area) and inner lining of
cavities(digestive tract&lungs)
 Some epithelial tissue undergo changes to form
glands(exocrine&endocrine glands)
 On skinforms a protective barrier against
infection,mechanical injuries & dehydration
 Lining of the human intestine form mucus-secreting
goblet cells which secrete mucus into the digestive tract
 Lining of the tracheaconsists of elongated cells called
cilia

6. 2. Muscle tissue
 Composed of cells called muscle fibres
 Have 3 types – smooth muscle, cardiac muscle, skeletal
muscle
(a) Smooth muscle(can be found in intestine,blood vessels,
urinary and reproductive tract)
- contraction&relaxationresponsible for involuntary body
activities(ex:perilstaltic movement)
- Contract more slowly than skeletal muscle but remain
contracted for a longer period of time
(b) Skeletal muscle
- Voluntary movementscontract & relax to move the bones
(c) Cardiac muscle
- Contract to pump blood (involuntary)

8. 3. Nerve tissue
 Composed of neurones
 Specialised to detect stimuli and transmit electrical
signals called nerve impulses to muscles or glands
 Control and coordinate activities of the body

10. 4. Connective tissue
 Consists of various types of cell and fibres separated by an
extracellular matrix
i. Loose connective tissuebinds epithelia to underlying
tissues and hold organs in place
ii. Dense fibrous connective tissuefound in tendons &
ligaments
iii. Cartilage strong&flexible;provides support to the
nose,ears and covers the ends of bones at joints
iv. Bone protection to organs and support the body
v. Blood cells  regulate,transport& protect
vi. Adipose tissue acts as an energy
reserve,insulation&protection

11. Red blood
cells
Bone

12. cartilage

14. Organs
 Is formed by two or more types of tissue working
together to perform a particular function
 Examples: heart,skin,lungs,kidneys,eyes and
ears

16. Systems
 Consists of several organs that work together to
perform a common function
 There are 11 major systems which carry out
major body functions in human

17. Cell organisation in plant
 Two main types:
(i)The meristematic tissues
- small cells which have thin walls, large nuclei,dense
cytoplasm & no vacuole
- Are young,actively dividing cell which have not
undergone differentiation and are located at the tips
of roots and the buds of the shoots

18. (ii) The permanent tissues
- Tissue that have undergone differentiation or are still
undergoing differentiation
- Have three types:
(a) Epidermal tissue
(b) Ground tissue
(c) Vascular tissue

19. 1. Epidermal tissue
 Outermost layer that covers the stem,leaves and
roots of young plants
 Are flat and have large vacuoles
 Cuticle minimizes water loss & prevent invasion
of diseases
 Root hairsincrease surface area for water
absorption
 Specialised epidermal tissue,ex: guard cells
control the opening & closing of stomata

20. Guard cell

21. 2. Ground tissue
 Consists of parenchyma tissue, collenchyma
tissue and sclerenchyma tissue
 Parenchymathin walls& large vacuole;store
sugar and starch
 Collenchyma supports herbaceous(non-woody)
plants
 Sclerenchyma have cell wall thickened by
lignin;give support & mechanical strength to
mature regions of a plant

24. Collenchyma cells

25. 3. Vascular tissue
 Consists of xylem & phloem
 Xylem transport water and mineral salts to all
part of the plant
 Phloem transport food(organic) substances to
all parts of the plant

28. Organs and systems in plant
 Organs  root,stem, leaf and flower
 Flowering plants have 2 systems:
(a) Root system  consists of all root of the plant
(b) Shoot system  consists of stem, leaves, buds,
flowers and fruits

30. Regulating the internal
environment
 What is internal environment?
- Refers to the environment inside an organism,
which is the fluid(blood plasma and interstitial
fluid) surrounding the cells

31. The necessity for maintaining an optimal
internal environment
 The physical factors and chemical factors of the
internal environment must be maintained for the
cells to function optimally
 Physical factor includes: temperature, blood
pressure & osmotic pressure
 Chemical factors: salt&sugar content, PH value

32. Homeostasis
 Is the maintenance of a relatively constant
internal environment for the cells to function
optimally
 Any increase in the value of a physical or
chemical factor will trigger the homeostatic
mechanism to bring it back to normal
 Any decrease will trigger the homeostatic
mechanism to raise it back to normal
 The mechanism that governs homeostasis is
called the negative feedback mechanism

33. The involvement of various systems in maintaining an optimal
internal environment
 Systems in the body function interact with one
another to maintain a stable internal environment
 For example: body temperature, concentration of
oxygen & carbon dioxide, the blood glucose level,
blood osmotic pressure, chemicals contents and
PH level

34. Body temperature
 Is regulated by the integumentary system(skin and sweat
glands), nervous system, circulatory system, muscular system
and endocrine systemBody temperature
RISES
The receptors in the skin detect the
changes
Information is transmitted to the
hypothalamus(temperature
regulatory centre in the brain)
activate
s
activate
sBlood
vessels
Sweat gland
Dilate and allow more
blood to flow near the
surface of the body
Increase heat loss to the
external environment
Produces more sweat that
will lower the body
temperature
Increase heat loss
through evaporation
Body
temperature
is restored to
normal

35. 2.3 Appreciating the uniqueness of the cell
 The state of certain cells without a particular
cellular components
Organelle missing Predicted state of the cell
Nucleus • All cell activities stop
• Cell does not live for long
• The cell dies
Mitochondrion • No energy for cell activities
• The cell dies
Ribosome • Cell is unable to synthesis enzymes (proteins)
• Cell growth stops
• Cell is unable to repair itself
• Finally, the cell dies
Endoplasmic
reticulum
• Less enzymes produced
• Synthesis and transport of proteins and glycerol
stop
Golgi Body • Proteins produced become defective
• Cell is unable to produce certain types of protein

36. Most of cells are specialised for the function that they
perform
1. Muscle cells
- Cell is able to contract
Specialised function  produces movement

37. 2. Neurone
- Shaped into a long thin fibre
Specialised function  conducts nerve impulses

38. 3. White blood cell
- Changes its shape
Specialised function  Engulf and destroys
microorganisms by phagocytosis

39. 4. Red blood cell
- Disc shape, biconcave and without nucleus
Specialised function  Transports oxygen (its nucleus is
absent so that there is more room to transport oxygen)

40. Exercises
1. How does an amoeba feed, move, reproduce,
respond to stimulus, grow, excrete waste, and rid its
body of excess water?
2. What are the problems of a multicellular organisms?
3. What advantages does a cockroach have over an
amoeba?
4. What is internal environment?
5. What are the four factors controlling the internal
environment?
6. What human body systems regulate:
(a) Body temperature
(b) Osmotic pressure
(c) Blood glucose level