Quick Review on Veterinary Physiology

FORMATION OF THREE GERM LAYERS

• All the embryonic germ layers originate from the epiblast, which divides into the endoderm, mesoderm, and ectoderm by a process called gastrulation.
• Christian Heinrich Pander (1794-1865) first identified this three layered organization in the blastoderm of embryonic chicks.
• In the process of gastrulation, a primitive streak first appears on the dorsal surface of the epiblast. As cells move past the primitive streak, they elongate and pass through to form ventral layers beneath the initial epiblast.
• At the end of the streak there is a small, well defined node - called Hensen's node. Migrating epiblastic cells that pass through this node form a mesenchymal structure called the notochord. By the end of gastrulation, a notochord and three distinct germ layers have form.

FERTILIZATION                                                                         

• The act or process of initiating biological reproduction by insemination or pollination.
• The union of male and female reproductive cells (gametes) to produce a fertilized reproductive cell (zygote).
• Fusion of a sperm cell with an egg cell to produce a zygote when the female sex cell (egg) and the male sex cell (sperm) come in contact.
• The joining of a sperm and an egg.
• The fusion of the male sex cell with the female sex cell to form an embryo is called fertilization

Study of the basic tissues of the body: Four basic tissue types

1. Epithelial tissues- Ectoderm, Mesoderm and Endoderm
2. Connective tissues - Mesoderm
3. Muscular tissues - Mesoderm
4. Nervous tissues - Ectoderm

The region of the digestive system with the CORRECT FUNCTION

• Pancreas - Produces the enzymes to digest proteins, fats and carbohydrates in the small intestine. Also produces the hormone insulin
• Tongue - Organ that mixes food in the mouth and makes swallowing happen
• Rumen - Micro-organisms digest cellulose in this modified part of the stomach
• Salivary glands - Produce saliva containing salivary amylase
• Oesophagus - Carries the food from the mouth to the stomach
• Gall bladder - Stores bile
• Pyloric sphincter - This muscle controls the passage of food out of the stomach
• Pharynx - Both food and air pass along this
• Rectum - Indigestible matter held here before defecation
•  Liver - Produces bile
• Stomach - A bag made of muscle where food is held. Gastric juice and hydrochloric acid are added here
• Small intestine - Where food is mixed with bile and digestion of proteins, fats and  carbohydrates takes place
• Colon - Water and salt are absorbed here
• Functional caecum - Where micro-organisms digest fibre in rabbits and horses

Digestive enzymes

• Carbohydrates e.g. Starch - Amylase → Glucose
• Fats or lipids - Lipase → Fatty acids and glycerol
• Proteins - Pepsin, protease → Amino acids

THE TERMS/VALUES

• 66%  - The proportion of the body’s water found within the cells
• Hypothalamus - The part of the brain concerned with controlling water balance
• 15% - The proportion of the body’s water an animal will not survive losing
• Thirst - This is the main mechanism for diluting the blood
• 80% - The proportion of an animal’s body that consists of water
• Kidneys - These organs are important for controlling water balance

STOMACH COMPARTMENTS

1. Reticulum - honeycomb  - (5% of capacity)
2. Rumen - paunch - (80% of capacity)
3. Omasum - manyplies - (7% of capacity)
4. Abomasum - true stomach - (8% of capacity)

The common words Relared to heart AND BLOOD

• The top two chambers of the heart are called atria.
• These structures stop blood flowing backwards into the atria Atrioventricular valves
• This side of the heart receives oxygenated blood. Left hand side
• This is the largest artery in the body. Aorta
• These are blood vessels that carry blood towards the heart. Veins
• This structure sets the speed of the heat beats. Pacemaker
• This blood vessel supplies the heart muscle with oxygenated blood. Coronary artery
• Most blood cells are made here. Bone marrow
• A hormone that increases heart rate. Adrenaline
• The pigment in red blood cells that enables them to carry large quantities of oxygen. Haemoglobin
• This mineral is necessary for blood to clot. Calcium
• A protein in the blood that is essential for clotting. Fibrinogen
• This vitamin is needed for blood to clot. Vitamin K
• A major symptom of this condition is the reduction of the amount of haemoglobin in the blood. Anaemia
• This plasma protein maintains the osmotic pressure of the blood. Albumin
• Red blood cells. Erythrocytes
• Each haemoglobin molecule contains 4 atoms of this. Iron
• These plasma proteins are antibodies. Globulins
• Most of the carbon dioxide is carried in the blood in this. Plasma
• The first hearts sound is produced by: The atrio-ventricular valves closing
• The second heart sound is caused by: The semilunar valves closing
• Ossa cordis are present in old sheep
• Red blood corpuscles or erythrocytes, which are made in the bone marrow.
• White blood corpuscles or leucocytes, which are made in the bone marrow, spleen and lymph nodes

The function of blood

• Transporting carbon dioxide to the lungs
• Transporting heat around the body
• Protecting the body from infection
• Producing new red blood cells. Red blood cells are made in the bone marrow

Events of one complete heart beat cycle in the correct order

• Deoxygenated blood flows from the caudal and cranial vena cavae into the right atrium
• The right atrium contracts
• The blood flows through the right atrio-ventricular valve into the right ventricle.
• The right ventricle contracts and blood flows along the pulmonary artery to the lungs
• The deoxygenated blood picks up oxygen
• Oxygenated blood flows along the pulmonary veins into the left atrium
• The left atrium contracts
• The blood passes through the left atrio-ventricular valve into the left ventricle
• The left ventricle contracts and blood flows along the aorta to the body

The blood vessel AND THEIR FUNCTION

• Pulmonary vein - Oxygenated Blood - Wall Thin - Flow towards the heart
• Aorta - Oxygenated Blood - Wall Thick - Flow away from the heart
• Pulmonary artery - Deoxygenated Blood - Wall Thick - Flow away from the heart
• Vena cava - Deoxygenated Blood - Wall Thin - Flow towards the heart

BLOOD CELLS

• Erythrocyte - Size 7.5 (µm) - Nucleus None - Granules in cytoplasm No - Function Transports oxygen
• Monocyte (Largest blood cell) - Size 10-30 (µm) - Nucleus Large and kidney shaped - Granules in cytoplasm No - Function Phagocytosis
• Granulocyte - Size 12-14 (µm) - Nucleus lobed - Granules in cytoplasm Yes - Function Combat infection (Phagocytosis/kill parasites/fight allergies/ release heparin)
• Lymphocyte - Size 9-14 (µm) - Nucleus Large and spherical - Granules in cytoplasm No - Function Kills invaders, makes antibodies
• Platelets - Size 2-4 (µm) - Nucleus Cell fragments - Granules in cytoplasm No - Function Blood clotting

Types of blood vessel in the correct order as blood would flow down them from the heart to the body and back to the heart again

ARTERIES, CAPILLARIES AND VEINS

1. Arteries: Structure of wall 3 layers, wall thick, Retain shape when no blood pass, Blood flow away from the heart, Speed of blood flow fast, Blood pressure high, No valve present, Palse present, Carry xygenated blood except pulmonary artery
2. Capillaries: Structure of wall 1 layers, wall very thin, Collapse when no blood pass, Blood flow From arterioles to venules, Speed of blood flow becoming slower, Blood pressure Decreasing as flows along capillary, No valve present, No palse present, Blood gives up oxygen as moves along
3. Veins: Structure of wall 3 layers, wall thin, Collapse when no blood pass, Blood flow towards heart, Speed of blood flow slow, Blood pressure low, Yes valve present, No palse present, Carry deoxygenated except for pulmonary vein 

LYMPHATIC SYSTEM

The function of lymph nodes: Filtering bacteria and debris from lymph. Organs of the lymphatic system (other than lymph nodes)

i. Spleen, ii. Thymus, iii. Lymph nodules e. g. Peyer's patches, iv. Bone marrow

Three functions of the lymphatic system

1. Filtering debris, bacteria etc. from the lymph.
2. Producing lymphocytes.
3. Returning fluid to the circulatory system.

Comparison of plasma, serum, tissue fluid and lymph in the cells

• Blood plasma: Clear fluid part of blood
• Serum: Fluid left when blood clots
• Tissue fluid: Fluid surrounding  cells. Formed from plasma
• Lymph: Fluid in lymphatic vessels

RESPIRATORY SYSTEM

The structures below in the order in which air passes them as it travels from the nose to the lungs are:  Pharynx; larynx; trachea; bronchi; bronchioles; alveoli

The oesophagus is part of the digestive system. The rest are parts of the respiratory system.

Statements in the right order to describe inspiration

• The muscles between the ribs contract to move the ribs up and out
• The diaphragm contracts and flattens
• The air pressure in the air tight pleural cavities decreases
• The lungs expand to fill the space created
• Air is drawn down the trachea into the lungs

The common words 

• Smallest respiratory passage way: Bronchioles
• Separates the mouth from the nose: Palate
• Windpipe: Trachea
• Where gas exchange takes place: Alveoli
• Stops food “going the wrong way” i.e. choking during swallowing:. Epiglottis
• Both air and food pass through this: Pharynx
• The movement of air out of the lungs: Expiration
• The main muscle involved in inspiration: Diaphragm
• Membranes that cover the lungs and line the pleural cavity: Pleura
• The volume of air inhaled or exhaled at each normal breath: Tidal volume

NEURONS OR NERVE CELL, WITH ITS FUNCTION

• Sensory neuron - The nerve cell that carries impulses from a sense receptor to the brain or spinal cord.
• Relay neuron - The nerve cell that connects sensory and motor neurons
• Motor neuron - The nerve cell that transmits impulses from the brain or spinal cord to a muscle or gland
• Axon - The long fibre that carries the nerve impulses
• Nerve - A bundle of axons
• Synapse - The connection between adjacent neurons.
• Neurotransmitter - The chemical secreted into the gap between neurons at a synapse
• Reflex - A rapid automatic response to a stimulus
• Myelin sheath - The covering of fatty material that speeds up the passage of nerve impulses
• Axon terminal - The structure at the end of an axon that produces neurotransmitters to transmit the nerve impulse across the synapse
• Nerve impulse - The high speed signals that pass along the axons of nerve cells
• Dendrites - The branching filaments that conduct nerve impulses towards the cell
• Sense receptor - The sense organ or cells that receive stimuli from within and outside the body
• Response - The reaction to a stimulus by a muscle or gland.
• Cell body - The part of the nerve cell containing the nucleus

Three different neurons involved in a reflex are from the stimulus to the response

Three different reflexes found in animals

Central Nervous System CNS) or the Peripheral Nervous System (PNS):- Brain - CNS, Autonomic nervous system - PNS, Spinal nerves - PNS, Spinal cord - CNS, Cranial nerves - PNS

DESCRIPTION OF THE TERMS

• Hypothalamus - Controls water balance and body temperature
• Medulla oblongata - Where the respiratory rate is controlled.
• Cerebellum - Where posture, balance and voluntary muscle movements are controlled.
• Cerebral hemispheres - Contains centers governing mental activity, including intelligence, Memory, and learning
• Meninges - The tough fibrous envelope enclosing the brain and spinal Cord
• Pituitary - The “master” gland of the endocrine system.
• Cerebral hemispheres/cortex - Responsible for instigating voluntary movements.
• Cerebrospinal fluid - The fluid that surrounds the brain and spinal cord.
• Grey matter - Composed of cell bodies and nuclei
• White matter - Composed of axons.
• Cerebral hemispheres/cortex - Where the sensations of sight, sound, taste etc. are interpreted
• Ventricles - Spaces in the brain filled with cerebral spinal fluid.
• Sulcus - A fold in the cerebral cortex.
• Carotid artery - The artery that supplies the brain with oxygenated blood

The descriptions with the parts of the nervous System

1. Part of the nervous system that is composed of the brain and the spinal cord - Central nervous system
2. Part of the nervous system that is composed of the cranial and spinal nerves - Peripheral nervous system
3. The part of the peripheral nervous system that regulates the activity of the heart and smooth muscle - Autonomic nervous system
4. The part of the autonomic nervous system that increases heart and respiratory rates, increases blood flow to the skeletal muscles and dilates the pupils of the eye - Sympathetic nervous system
5. The part of the autonomic nervous system that increases gut activity and decreases heart and respiratory rates - Parasympathetic nervous system

NERVES WITH THEIR FUNCTION

• Vestibular nerve: The 8th cranial nerve that carries impulses from the organs of balance and hearing to the brain.
• Optic nerve: The 2nd cranial nerve that carries nervous impulses from the retina of the eye to the brain.
• Sciatic nerve: The largest nerve in the body serving the muscles of the leg.
• Olfactory nerve: The 1st cranial nerve that carries impulses from the organ of smell in the nose to the brain.
• Vagus nerve: The 10th cranial nerve that supplies the pharynx, lungs, heart, stomach and most of the abdominal organs

Antidiuretic hormone (ADH)

• ADH is produced by the posterior pituitary gland/hypothalamus
• ADH acts on the walls of the collecting ducts of the kidney tubule.
• When no ADH is produced an animal is said to have the condition known as diabetes insipidus
• ADH makes the walls of the collecting ducts permeable to water.
• ADH is secreted when the blood becomes too concentrated.
• When an animal is dehydrated lots of ADH is produced.
• The main symptom of a failure to produce ADH would be lots of dilute urine

TERMS RELATED TO EYES WITH THEIR DESCRIPTION

• Aqueous humour - Fluid that fills the anterior chamber of the eye.
• Sclera - The white of the eye.
• Blind spot - Area of the retina that lacks rods and cones.
• Retina -Layer containing the rods and cones.
• Vitreous humour - Jelly-like substance filling the posterior cavity of the eyeball.
• Choroid - Heavily pigmented coating that prevents light scattering within the eyeball: reflects light in nocturnal animals.
• Iris - Coloured structure that controls the size of the pupil.
• Fovea- Area of the retina of most detailed vision.
• Cornea - Most anterior part of the sclera—the window on to the world.
• Sclera - Outer coating of tough, fibrous connective tissue.
• Pupil - Aperture of the eye. Where the light enters.
• Conjunctiva - The delicate membrane that covers the front of the eyeball.
• Nictitating membrane - The third eyelid
• Optic nerve - The nerve that takes nerve impulses from the retina to the brain.

TERMS RELATED TO EARS WITH THEIR DESCRIPTION

• Eustachian tube- Connects the pharynx (throat) and the middle ear to keep the air pressures equal.
• Tympanic membrane or ear drum - Vibrates as sound waves hit it. Transmits these vibrations to the auditory ossicles.
• Ear pinna - Animals can turn this towards the direction of the sound.
• Auditory ossicles - The smallest bones in the body. They transmit sound vibrations across the middle ear.
• Cochlea - Sound vibrations are converted here into electrical impulses.
• Vestibular organ - Contains receptors for the sense of balance and movement.
• Ear canal - This canal can harbour mites in cats and dogs.
• Inner ear - The part of the ear consisting of the cochlea and vestibular Organ
• Middle ear - The part of the ear that contains the ear ossicles
• Auditory nerve - The nerve that transmits nerve impulses from the cochlea to the brain
• Parts of the ear in the order in which sound waves travel to stimulate the cochlea

Statements related to ears

• There are two parts to the vestibular organ. The first part consists of the semicircular canals which respond to changes in speed and direction of movement of the body.
• The canals are filled with fluid and fine hairs that are stimulated when the head moves.
• The receptor cells send nerve impulses along the vestibular nerve to the cerebellum in the brain.
• The otolith organs form the second part of the vestibular organ. They contain tiny pieces of chalk called otoliths that stimulate hair cells and tell the animal which way up it is.
• The special sense organ for taste is located on the tongue.
• The sensory cells concerned with smell are called the olfactory organ. This is located in the nose.
• In the skin, cells that sense temperature, pressure and touch are found.

SKIN

• The outermost layer of the skin is: the epidermis
• The thickest layer: the dermis
• Sebaceous glands secrete: oils
• Sweat glands are: exocrine glands
• Sense organs for touch, pressure, pain and temperature are found in the: Dermis
• Temperature regulation is under the control of the: hypothalamus
• Vitamin is produced in the skin in sunlight: Vitamin D
• Large animals find it easier to keep warm than small ones because: the ratio of the outside body surface area to the inner body volume is smaller
• Frogs and other amphibians use their skin for: gas exchange attracting a mate.

 STOMACH

• Largest part of stomach: →Rumen,  True stomach: →Abomasum, 
• Glandular stomach:→ Abomasum, Suckling stomach: →  Abomasum

 LINKAGE BETWEEN

Bone to bone:→Ligament, Muscle to muscle:→Aponeurosis, Bone to muscle:→ Tendon

DERIVED FROM

Male genital tract:→Mullerian duct, Female genital tract:→Wolffian duct, Nervous tissue:→Ectoderm, Muscular tissue:→ Mesoderm, Epithelial tissue:→Ecto/Meso./Endoderm

PRESENT IN

Margo plicatus in the stomach of: →Horse, Bulbus glandis in the penis of:→Dog, Payers patches in part of stomach:→Ileum, Os penis in visceral bone found in:→ Dog

ABSENT IN

Gall bladder:→Horse, Vas deference:→ Pig, Seminal Vesicle:→Bore, IgD immunoglobulin:→Bovine

LARGESST/LONGEST/SMALLEST

Largest virus:→  Pox virus, Smallest virus:→Picorna (20nm), Largest muscle:→Gluteus maximus, Longest muscle:→ Longissimus dorsi, Longest ligament:→ ligament Nouche, Strongest tendon: → Acilus tendon, Largest cranial nerve:→ Trigeminal, Largest gland in the body:→ Liver, Smallest toxon:→ Species

COLOSTRUMS

• Contains high level of coagulable protein
• It should be fed within 30 minutes of parturition
• It must be fed 1/10th of the calf body weight
• Milking should be completed within 7 minutes
• Hepatic portal vein 75% of the blood to the liver is from the GI system.
• Hepatic artery 25% of blood to the liver is from systemic circulation.
• Hepatic vein blood leaves the liver.
• Glycogen storage in liver cells
• Hemoglobin released serves as the major source of bilirubin.
• Heme groups are converted into bilirubin by spleen, liver and bone marrow.