The Exterior, Nervous, Urinary, and Endocrine Systems of Domestic Animals

Animal ScienceIMS 8646-F

Introduction An agricultural producer should be

knowledgeable of that A&P of livestock.

We will discuss 4 systems throughout these notes.

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

CNS

PNS

Functions of the Nervous Sys. 1. To organize physical movement

2. Respond to the actions of all the senses, either internal or external

Nerves

Consists of 2 parts: Neuron = nerve cell

Axon = long fiber Dendrites = branched

Synapse Point at which the dendrite

connects to the axon

Parts of the Brain Cerebrum

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

Cow’s Brain

Sheep and Pig’s Brain

Human Brain

Spinal Cord The main avenue for message

transferals Divided into 5 segments: what are

they?

External Anatomy Skin is the largest organ! Hair, wool, horns, feathers,

toenails, and hooves are modified extensions of the skin

What is cloven hooves?

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.

Skin

Consist of two layers: Epidermis

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

Primary Glands Sweat glands Sebaceous glands

Secrete oily substances to lubricate the skin and hair

Sweat Gland

Sebaceous gland

UrinarySystem Consists of:

Kidneys Ureters Bladder Urethra

Kidneys Located in the abdominal cavity

just under the lumbar vertebrae Consists of:

Renal cortex = outer portion Renal medulla = inner protion

Kidneys

Functions of kidneys 1. Filter waste products form the

blood

2. Regulate blood composition

Ureters Are tubules that connect the

kidneys with the bladder and transport urine from to bladder as well.

Bladder An expandable sac that stores the

urine until it is expelled from the animal’s body

Urethra Elastic tubule that carries urine

from the bladder outside the body

Chickens don’t have one.

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.

Pancreas In females releases oxytocin and

that causes an immediate release of milk in lactating females

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.

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.

Hypothalamus Located above the pituitary gland

and regulates the functions. Hormones produced here are

transported by means of portal blood vessels

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.

Vocabulary Terms Autonomic Nerves Hormones Somatic Nerve Glands