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Ministry of Education

Secondary Engagement Programme

September 2020

Grade 9

Agricultural Science

Week 1

Lesson # 2

Topic: Anatomy and Physiology of Farm Animals

Subtopic: Physiology of Farm Animals

Definition

Physiology refers to the study of how internal structures function with in the living body

The important body processes, characteristics of living organisms include the following:

*movement *feeding *reproduction * Growth

*sensation *excretion *respiration

These processes operate in different systems of the animal’s body. Each systems has organs

which are made up of tissues.

Transverse section of the pancreas showing the arrangement of tissues

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Movement

- Most farm animals are able to move from one place to another by means of bones and muscles

within their bodies.

-the point where two bones meet is called a joint

- Bones are kept together by strong elastic bands called ligaments.

- The ends of bones are usually covered by a smooth but tough substance called cartilage.

- Synovial fluids occupies the space between the end of the bones.

The longitudinal section of a joint

Sensation

- Animals can respond to environment stimuli. This is so because nerve fibres are distributed

throughout their bodies.

- Nerves fibres are connected to the spinal cord and the brain is found in the skull.

- The brain is the control center of all voluntary actions

-When there is a reflex action, the stimulus(pain) is transmitted from the skin to the spinal cord

by the special nerve fibres called sensory neurons.

- The message from the spinal cord is now transmitted to the muscle fibres by the motor neurons

for response action.

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The Nervous system of a cow

Respiration

- This involves breathing and the chemical breakdown of simple sugar within the cells to

produce energy.

- 𝐶6𝐻12𝑂6 + 602 → 6𝐶𝑂2 + 6𝐻2𝑂 + 𝐸𝑛𝑒𝑟𝑔𝑦

Simple sugar +Oxygen → Carbon + water and energy

(glucose) dioxide

- Air reaches the lungs by passing through the nostrils, pharynx, trachea, bronchi and

bronchioles.

- The bronchioles with in lungs end in clusters of air sacs called alveoli.

- Oxygen in the blood cells (oxygenated blood) is taken to all body cells to take part in cell

respiration.

The Respiratory system of Fowl

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Feeding

- Food ingested needs to be physically broken down into much smaller size.

- Digestive enzymes can split up chemically complex foods to simpler substances.

- These activities occur in the digestive system which consists of an alimentary tract.

- Based on the differences of the alimentary tract, farm animals are classified as ruminants and

Non-ruminants or monogastric animals.

Alimentary canal

of a pig

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Alimentary canal of a Goat

Excretion

- Farm animal can get rid of waste substances from cells within their bodies through two main

organs – the kidneys and the skin.

- In the kidneys, the blood is filtered to separate the waste substances from the blood cells and

blood plasm.

- Attached to the kidney are muscular tubes called ureters which carry urine from the kidneys to

the bladder

- Attached to the bladder is the urethra.

- By the time the urine gets to the ureters it is concentrated.

- urine is transported to the bladder where it is stored until excreted from the body.

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The parts of the urinary system

The skin

- The skin has two layers of tissue, the epidermis and the dermis.

- The skin function as an excretory organ because of the sweat glands which secrete sweat

containing water, salt, small amounts of urea and lactic acids.

- Although all farm animals have sweat glands, only horses sweat readily

The parts of the skin

Growth

- In animals, normal body growth occurs when there is an increase in body size of the animal.

- Body cells of an animal have identical chromosomes occurring in pairs in the nucleus of a cell.

- chromosomes are threadlike structures which carry genetic material (genes) of animals.

- The number of chromosomes of a particular animal is constant, that is, cattle -30 pairs; Sheep-

27 pairs; pig- 19 pairs; Chicken – 39 pairs of chromosomes.

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Simplified diagram of a pair of Chromosomes

Reproduction

- Sexual reproduction is the biological process whereby the male sex cell fuses with the female

sex cell to produce a zygote.

- Mammals on the farm would produce no milk if parturition does not occur.

- The reproduction process is vital, if egg production and meat production are to be sustained.

- Mammals produce their young ones once alive, whereas birds lay ova which must be incubated

outside of their bodies before the young ones emerge

- The mammalian young obtain milk from their mother’s udders while the young birds obtain

nutrients from the yolk of their eggs during the first forty-eight (48) hours after hatching, they do

not take milk.

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The Female Reproductive organ

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References

Sahadeo Ragoonanan (2011) ‘Agriculture for CSEC Revision course’ New Edition,

Caribbean Educational Publisher Ltd, Trinidad, WI

Fitzroy Weever et al (2014) Agricultural Science for Secondary Schools in Guyana, Book

3, Ministry on Education NCERD, Georgetown, Guyana

Sahadeo Ragoonanan (1991) CXC Agriculture- A Revision Course, Caribbean

Educational Publisher Ltd, Trinidad, WI

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Exercises

1) Name the two substance when combine together reduce friction between two bones

during movement

2) Explain why animals can respond to environmental stimuli

3) Create an example of a conditioned reflex action that a farmer can used for easy milk let-

down during milking time.

4) Explain one difference between ruminants and Non ruminants based on the alimentary

tract.

5) The skin functions as an excretory organ.

Explain the statement above

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