Transcript General Physiology - Animal Sciences Home Page

General Physiology
SAG 106 - ANSC 101
Dale M. Forsyth
PHYSIOLOGY is functions and activities
of the organs, tissues and cells of
organisms.
The field of physiology includes:
Body Fluids: blood, lymph, cerebrospinal
fluid, synovial fluid.
Circulation: heart, blood vessels, control
physiology includes:
Respiration: mechanics, transport &
exchange of gasses, regulation
physiology includes:
Digestion and Absorption:
already covered, could consider more
physiological aspects
Thermoregulation
physiology includes:
Excretory system:
Kidneys, sweat glands
physiology includes:
Muscular system:
muscle action, mechanisms, types
Skeletal system:
bones
physiology includes:
Nervous system:
action of nerves,
spinal cord, brain,
brain stem, parts of
the brain, sensory
organs
Endocrine system:
hormonal control of
the body
physiology includes:
Reproductive system:
Follicles
how animals
reproduce,
glands and organs
regulation
Ovaries
Blood
The primary functions of the blood are:
 1. carry nutrients to the tissues
 2. carry O2 to the tissues
 3. remove waste from the tissues
Blood is composed of
Fluid part, PLASMA
Cells (corpuscles)
RBCs - red blood cells (erythrocytes)
WBCs - white blood cells (leucocytes)
RBC contains Hemoglobin, the O2 carrying
material
WBC - leukocytes - are disease fighters
The HEART
is responsible for pumping the blood
throughout the body.
AMAZING ORGAN.
Works all the time you are alive.
Actually, it rests 2X as much as it works,
though.
systole
vs
diastole
contraction
relaxation
Blood follows the path:
left ventricle
pulmonary artery
aorta
lungs
arteries (leaving heart)
pulmonary vein
capillaries
left atrium
veins (returning to heart)
left ventricle
right atrium
right ventricle
Control of the heart
regulated by the AUTONOMIC nervious
system (vs SOMATIC nervous system)
Rate of heart beat:
Horse
32-44
Cow
60-70
Man
60-90
Cat
110-130
Chicken
200-400
RESPIRATION breathing
gasseous exchange between animal and its
environment
Consists of: Lungs and air passages
Purpose: bring in Oxygen, eliminate CO2
Air is about 21% O2, 79% N, trace of CO2
expired air is 16% O2, 79% N, and 5% CO2
Expired air is:
heated to about body temperature
saturated with water vapor
SO, breathing causes heat loss AND
water loss from the body
Exchange of gases in blood and inspired
air takes place in the lungs, in the
capillary beds there. Blood takes up O2
and gives up CO2.
The brain and other organs needs a
constant supply of OXYGEN to function.
FROM A PRACTICAL STANDPOINT
livestock buildings need proper ventilation
to allow proper gas exchange to take
place in an animal's lungs
VERY IMPORTANT
SOMETIMES NEGLECTED
Control of Respiration:
Central Nervous System
also by chemicals in the blood
Kidney Function
Main function:
keep composition of blood plasma
constant, ie maintain HOMEOSTASIS, by:
1. excretion of nitrogen containing waste
products
2. elimination of inorganic minerals
3. elimination of H2O
4. elimination of non-volatile, soluble foreign
substances
Nervous System
Control of the body,
communication between
its parts
3 main parts
Brain
Spinal cord
Periperhal nerves
Brain
Cerebrum
largest part
think center
memory
Cerebellum
coordinates brain's other centers and mediates,
e.g. muscular activity, eating, talking, etc.
Brain
Pons & Medulla oblongata
control reflex actions, such as breathing,
swallowing, vomiting, etc.
They act independently of the cerebrum and
cerebellum
Brain
Hypothalmus
Center of Control of autonomic nervous
system
semi-automatic control of glands, blood
vessels, heart, viscera, and other smooth
muscles
Spinal cord
 in center of vertebral column
 pathway of nerves from brain to
peripheral nerves
Peripheral nerves
All outside the brain and spinal cords
 Motor or efferent nerves - from brain or
spinal cord to periphery
 Sensory or afferent nerves - from outside to
spinal cord or brain
All these systems working together
are necessary to make an animal
work properly
We have little time to consider all
of general physiology, but all
these systems working together
are necessary to make an animal
work properly.
One system we want to spend a
bit more time with is a system that
helps control all the others, and is
especially important in
reproduction, which we will be
considering in more detail. This is
the HORMONE system or
ENDOCRINE system.
Endocrinology
A hormone is:
A substance produced in one part of the
body that flows through the blood stream and
has its effect at some other target location.
An endocrine gland is:
A ductless gland
One that produces hormones
Endocrine glands
That secrete only hormones:






Thyroid
Parathyroid
Pituitary
Adrenal
Pineal
Thymus
Endocrine glands
That secrete hormones AND other
substances:





Pancreas
Testicle
Ovary
Gastric epithelium
Intestinal epithelium
Thyroid gland
 Located in neck region
 Present in all animals
 Bi-lobed in most species
 THYROXIN – regulates basal metabolic
rate, rate at which cells metabolise
Made up of amino acid & Iodine
 Also secretes calcitonin, lowers Ca level
Parathyroid glands
Near or in thyroid
 2 pair, tiny, (size of a BB)
PARATHYROID HORMONE
 causes release of Calcium from the bone to
the blood
Pituitary
 Regulator of Regulators
 Controls the other hormone-producing glands
 Small (size of pea in man)
 Located at base of brain
 2 lobes, anterior and posterior
Anterior pituitary
ACTH - adrenocorticotrophic hormone
 controls function of adrenal cortex
Growth Hormone - Somatotrophin (BST)
 Regulates growth
 TSH - thyroid stimulating hormone
 Controls thyroid and thyroxin release
Anterior pituitary (continued)
 GONADOTROPHINS (more on these later)
 FSH – Follicle Stimulating Hormone
 Develops ova and follicle
 LH – Luteinizing Hormone
 Causes ovulation
 Prolactin – maintains lactation
Posterior pituitary
 Vasopressin
 Maintains blood pressure
 Oxytocin
 Contraction of the uterus at parturition
 Milk letdown
Adrenal glands
2 glands, 1 near each kidney
2 parts, inner (medulla) and outer (cortex)
Adrenal Cortex
 Adrenocorticoids – steroids
 mineral corticoids – regulate mineral excretion
 glucocorticoids – regulate energy from CHO
Adrenal Medula - Epinephrine
Adrenal glands (continued)
Adrenal Medula – Epinephrine &
Norepinephrine






Functions especially in stress conditions
States of emergency
Increases heart rate
Increases blood pressure
Mobilizes glucose
Enables superhuman feats
Pineal gland
 Response to environment, especially light
Thymus
 Antibody production in the young
HORMONES FROM GLANDS
THAT ALSO SECRETE
OTHER SUBSTANCES - both
ENDOCRINE & EXOCRINE
GLANDS
Pancreas
 Insulin
 Gets glucose into cells
 Lowers blood glucose
 Glucogon
 Raises blood glucose levels
 Stimulates glycogen to glucose
Testicle
Testosterone
Small amounts of estrogen
Ovary
 Estrogen
 From follicle
 Progesterone
 From Corpus Luteum
Gastric & Intestinal
epithelium
Several hormones controlling digestion




Pancreozymin
Cholecystokinin
Gastrin
Enterogastrone
End of General
Physiology/Endocrinology
Next: Reproductive
Physiology