Anatomy And Physiology Of Farm Animals: Digestive, Circulatory and Reproduction system
Subject:
Agricultural Science
Class:
SSS 1
Term:
Third Term / 3rd Term
Week:
Week 4
Topic:
Anatomy And Physiology Of Farm Animals: Digestive, Circulatory and Reproduction system
Previous Knowledge: The pupils have previous knowledge of
FARM MECHANIZATION (TRACTORIZATION)
that was taught in their previous lesson.
Behavioural Objectives : At the end of the lesson, learners will be able to
- Define Anatomy And Physiology Of Farm Animals
- State Digestive, Circulatory and Reproduction System of farm animals
Instructional Materials
- Wall charts
- Online Resource
- Textbooks
- Laptop
- Wikipedia
Methods of Teaching
- Role modelling
- Questions and Answers
- Explanation
- Discussion
- Recitation
- Imitation
- Story Telling
- Dramatization
WEEK FOUR
ANATOMY AND PHYSIOLOGY OF FARM ANIMALS
CONTENT
- Digestive system
- Circulatory system
- Reproduction system
DIGESTIVE SYSTEM
- Digestive system and digestion
- Digestion in ruminant (polygastric) animals
- Digestion in non-ruminant (monogastric) animals
- Digestion in poultry birds
- Differences between monogastric and polygastric animals.
DIGESTIVE SYSTEM AND DIGESTION
The digestive system of farm animals includes all the organs and tissues associated with the breaking down or digestion of food in the body. It includes the teeth or beak, tongue, the alimentary canal or digestive tract and all the associated gland secreting enzymes and other body fluids.
Digestion is the breakdown of foods substances in the digestive tract into absorbable forms. This process starts from the mouth through mastication which increases the surface area and allows microbes to have quicker access to act the food substances.
Farm animals are grouped into two main classes based on the nature of the alimentary canal or digestive tract. There are polygastric (ruminant) animals and monogastric (non – ruminant) animals.
DIGESTION IN RUMINANT ANIMALS
These are farm animals which possess complex stomach made up of four compartments or chambers. These are rumen (paunch) which is the first, reticulum or fore stomach (honey comb), omasum(the fardel, manyplies or psalterium) and abomasum (true stomach). These animals can ruminate or chew the cud. Exampleof farm animals having this stomach compartment includes cattle, sheep, goat etc.
Cattle for example when feeding gather some quantity of grasses with its tongues and grip it firmly between the upper jaw and the teeth of the lower jaw; it jerks its head and swallows the grasses. The grasses pass through oesophagus and enter the rumen, where digestion of cellulose by bacteria takes place.
When the cattle has filled its rumen, it lies down quietly and by anti–peristaltic movement of the stomach the undigested grass or cud passes from the rumen to the reticulum from where it goes back to the oesophagus and back to the mouth to be masticated (this process is referred to as regurgitation). It then chews the food properly into a semi-liquid cud (bolus) with the premolars and molars which re-swallowed. The cud moves into the omasum and passes into the last chamber, abomasum where gastric juice containing digestive enzymes are secreted into the semi–digested food to form the chyme. The chyme goes into the small intestine through the duodenum where further digestion and absorption of nutrients takes place. The undigested material then passes out through the anus as dung.
DIGESTION IN NON-RUMINANT ANIMALS
These animals possess only one stomach structure and they do not ruminate (that is they do not chew the cud). The animals cannot digest cellulose and fibers properly. Examples include pigs, poultry etc. Pig has a simple stomach. It feeds mainly on basal feeds like maize, cassava and other meshed food. Digestion of foods takes place in four area of the tract.
- Mouth: In the mouth, the food is changed and mixed with saliva which contains an enzyme Ptyalin. Ptyalin converts starch to maltose. The food (bolus) is then swallowed and moved by peristaltic movement to the stomach.
- Stomach: here, two enzymes, pepsin and rennin are present. Renin act on milk and pepsin convert protein to peptones. The thick liquid formed(chyme) now passes to the duodenum.
- Small intestine
Duodenum:Here, the pancreas secretes pancreatic juice which contains three digestive enzymes i. e.
- Amylase – Converts starch to maltose
- Lipase – Converts fats and oil to fatty acid and glycerol
- Trypsinogen – Converts protein and peptones to polypeptides
The digestion of fats and oil is aided by bile. Bile helps in the emulsification of fats. At the duodenum, the food now in liquid form called chyle passes to the ileum of the small intestine. In the Ileum,secretion of enzymes which furthers the process of digestion takes place. These enzymes are
- Lipase – convert fats and oil to fatty acid and glycerol
- Erepsin – Converts polypeptides to amino acid
- Maltase – Converts maltose to glucose
- Lactase – converts lactose to glucose and galactose
- Sucrase – converts sucrose to glucose and fructose
The end product in the digestion of protein is amino acid, starch is glucose and fats and oil is fatty acid and glycerol.
DIGESTION IN POULTRY BIRDS
The domestic fowl is a monogastric animal that possesses a simple stomach. The fowl has no teeth but the food is picked up by the beak. The food then passes on to the crop through oesophagus. The food is stored temporarily in the crop, there moistened and fermented by some bacteria. The food now passes on to the proventriculus (glandular stomach) where digestive juice such as pepsin and amylase are secreted on the food.
From the proventriculus, the food moves to the gizzard where grinding of the food takes place. From the gizzard, the food moves to the small intestine where further digestion and absorption takes place. The undigested food materials are removed from the digestive tract as faeces.
DIFFERENCES BETWEEN MONOGASTRIC AND POLYGASTRIC ANIMALS
| S/N | MONOGASTRIC | POLYGASTRIC |
| It cannot ruminate or chew cud | It can ruminate or chew cud | |
| Feed is mainly basal and concentrated food | Feed is mainly grasses and other cellulose | |
| Possess one stomach compartment | Possess four stomach compartment | |
| It cannot digest cellulose and fiber properly | It can digest cellulose and fiber very well | |
| Digestion is not aided by bacteria | Digestion is aided by bacteria | |
| It cannot synthesis their own protein | It can synthesis their own protein |
CIRCULATORY SYSTEM
Circulatory system consists of all the tissues and organs that are involved in the transportation of materials through the blood round the body offarm animals. Farm animals possess closed circulatory system. This means that oxygenated and deoxygenated blood does not mix. They also display a pattern of double circulation(this mean that for one complete circulation to occur, the blood must pass through the heart twice; first to the lungs for oxygenation and then on return to the other parts of the body) or single circulation as in the case of fish.Circulatory system has three (3) main divisions. These are:
- The Blood
- The Blood vessels, and
- The Heart
THE BLOOD: Mammalian blood is made up of plasma andblood Cells, which are;
- Plasma-liquid part of the blood. It contains water, blood proteins (e.g fibrinogen),dissolved mineral salt, waste product, digested food.
- The Blood Cells(corpuscles)
- Red blood cells (Erythrocytes): biconcave, circular in shape and no nucleus when matured, contain iron pigment called haemoglobin that helps to transport oxygen, produced in bone marrow,
- White blood cells (Leucocytes): irregular in shape, few than red blood cells, have nucleus, produced in lymphatic tissues. They defend the body against foreign bodies.
- Blood platelets (Thrombocytes): irregular or star-shaped, tiny, non-nucleated, produced for blood clotting.
FUNCTIONS OF THE BLOOD
- Maintain body temperature through uniform distribution.
- Carries oxygen through the red blood cells.
- Transports hormones from ductless gland
- Transport metabolic waste to where they are removed.
- Defend body against germs via leucocytes
- Platelets help in blood clotting
- Transports digested food to cell.
- Maintain water level and turgidity of the body
THE BLOOD VESSELS: these are a network ofspaces in the body through which material are movedfrom one part of the body to the other with the aid of blood. There are three major blood vessel, they are:
- Artery: carries blood away from the heart to other part of the body. It further divides into arterioles.
- Vein: this vessel caries blood back to the heart from other parts of the body. It further divides to form veinous.
- Capillaries: tiny bloods vessel around tissues and organs where arteries and veins
meets.
THE HEART: This is a muscular organ responsible for pumping blood round the body. Each pump action of the heart isknown a heartbeat. The heartis located in the thoracic cavity of the body, protected by the pericardium. It consists offour chambers:the upper: auricle (right and left), the lower: ventricles (right and left). A central wall divides the right and left part of the heart called septum. The auricles and ventricles are divided on the right by a tricuspid valve and on the left by a mitral/bicuspids valves.
Presentation :
The topic is presented step by step
Step 1: The class teacher revises the old topic
Step 2: The class teacher introduces the new topic
Step 3: The class teacher allows the pupils to give their own contributions and gives room for pupils” participation
Class Teacher and Pupils Activities. Interaction or Participation
This involves class teacher and pupils’ interaction, conversation, imitation or modeling through discussion, play method or just by recitation or asking and answering questions that are related to the topic that has just been taught.
EVALUATION
- What are non-ruminant animals?
- List the digestive enzymes in
- A. stomach
- B. small intestine
- C. pancreas
- D. liver and their functions.
- Describe briefly digestion in domestic fowl.
- Differentiate between ruminant and non-ruminant animals.
- What is circulatory system?
- List the functions of blood.
Conclusion :
The class teacher concludes the lesson by giving the pupils some notes on the topic that has just been taught. He goes round to mark and he does the necessary corrections.