1. The Exterior, Nervous, Urinary, and Endocrine Systems of Domestic Animals
Animal Science
IMS 8646-F

2. Introduction
An agricultural producer should be knowledgeable of that A&P of livestock.
We will discuss 4 systems throughout these notes.

3. Nervous System Consists of two major parts:
The Central Nervous System (CNS)
Brain
Spinal Cord
The Peripheral Nervous System (PNS)
Somatic Nerves
Nerves that control voluntary movements
Autonomic Nerves
Nerves that control involuntary actions like the heart, intestines, and glands

4. CNS

5. PNS

6. Functions of the Nervous Sys.
1. To organize physical movement
2. Respond to the actions of all the senses, either internal or external

7. Nerves Consists of 2 parts: Neuron = nerve cell Axon = long fiber
Dendrites = branched

9. Synapse
Point at which the dendrite connects to the axon

10. Parts of the Brain Cerebrum Cerebellum Pons & Medulla Oblongata
Largest part, relative to body size in smarter animals
In charge of thinking process, reacts to sense stimuli
Cerebellum
Coordinates messages for transmission to the body
Controls muscle performing activities, if damaged incoordination may result, but not paralysis
Pons & Medulla Oblongata
Together control reflex actions
i.e. blinking, vomiting, breathing, swallowing
Independent

11. Cow’s Brain

12. Sheep and Pig’s Brain

13. Human Brain

14. Spinal Cord The main avenue for message transferals
Divided into 5 segments: what are they?

15. External Anatomy Skin is the largest organ!
Hair, wool, horns, feathers, toenails, and hooves are modified extensions of the skin
What is cloven hooves?

16. Functions of Skin
To protect against disease and infection and to regulate body temperature.
Contains glands for secretion and excretion and sensory nerves to help animals react to their environment.

17. Skin

18. Consist of two layers: Epidermis Dermis
Outer layer of the skin and contain no blood cells
Dermis
Inner layer of the skin and contains blood vessels, lymph vessels, nerves, glands, hair follicles, and muscle fibers

19. Primary Glands Sweat glands Sebaceous glands
Secrete oily substances to lubricate the skin and hair

20. Sweat Gland

21. Sebaceous gland

22. Urinary System
Consists of:
Kidneys
Ureters
Bladder
Urethra

23. Kidneys
Located in the abdominal cavity just under the lumbar vertebrae
Consists of:
Renal cortex = outer portion
Renal medulla = inner protion

24. Kidneys

25. Functions of kidneys 1. Filter waste products form the blood
2. Regulate blood composition

26. Ureters
Are tubules that connect the kidneys with the bladder and transport urine from to bladder as well.

27. Bladder
An expandable sac that stores the urine until it is expelled from the animal’s body

28. Urethra
Elastic tubule that carries urine from the bladder outside the body
Chickens don’t have one.

29. Endocrine System
Many cells in the animals body rely on the interaction of chemical substance that are secreted by the endocrine glands.
The glands are small and located in various parts of the body.
They secrete hormones into the bloodstream.

30. Pancreas
In females releases oxytocin and that causes an immediate release of milk in lactating females

31. Hormones
After being secreted in the bloodstream they perform specific duties including growth, fattening, reproduction, lactation, and egg laying. The animal production depends on the level of the correct hormones.

32. Pituitary gland Master Gland Anterior pituitary Controls hormones
If removed the animal will not grow or reproduce. The other glands will then shrink and stop functioning.

33. Hypothalamus
Located above the pituitary gland and regulates the functions.
Hormones produced here are transported by means of portal blood vessels

34. Thyroid Located on either side of the trachea. Produces Thyroxine
Controls growth and energy production.
Calcitonin a hormone produced by the thyroid controls blood levels of calcium and bone density.

35. Vocabulary Terms
Autonomic Nerves
Hormones
Somatic Nerve
Glands