Transcript Importance of the Equine Industry

Describe Anatomy and
Physiology of Horses
Equine Science
For sixty seconds, write down every body
function you are currently using, some
without thinking about it.
For example, you are breathing—that
would be respiratory system.
Just like you have systems in
your body to ensure proper
health, so does the horse.
There are many systems to study. Today we
will introduce each major system in the horse.
Objectives
Today we will:
Describe the
Describe the
Describe the
Describe the
Describe the
Describe the
Describe the
digestive system
skeletal system
muscular system
reproductive system
nervous system
circulatory system
respiratory system
The Digestive System

The digestive system is responsible for the
breakdown and absorption of nutrients.

Its parts, in order from front to back, are called
the mouth, pharynx, esophagus, stomach, small
intestine, cecum, large colon, small colon and
rectum.

The alimentary canal is roughly 100 feet long in
an average horse, but the stomach is relatively
small, holding 3-4 gallons when full. This is one
reason it is better to feed horses small quantities
at frequent intervals.
Digestive
System
http://www.google.com/imgres?imgurl=http://3.bp.blogspot.com/uydvXqvEUQ8/TZyuoaTa0QI/AAAAAAAAASw/qCN2mJh0yi0/s1600/digestive_system.jpg&imgrefurl=https://www.pinterest.com/lmalyk/horse-worksheets/&h=300&w=450&tbnid=3gw3kHOY3YtGjM:&zoom=1&docid=uxIkxa_QYdBQ1M&ei=vHtzVZL2IdLYoAShuoCYAQ&tbm=isch&ved=0CC4QMygSMBI
The Skeletal System

Horses are members of phylum Chordata, sub-phylum
Vertebrata. They have an internal skeleton which include
a backbone.

The horse's "backbone" stretches along the topline from
the poll in front into the tail in the rear, and is not
actually a single bone, but linked vertebrae.

The horse's skeleton as a whole supports the horse's body,
defines the basic shape or framework, protects delicate
internal organs and provides attachment points for the
muscles that make movement possible.

It also houses the bone marrow, which is where blood cells
form. Ligaments help connect bones.
Skeletal
System
http://www.thinklikeahorse.org/images/horseanatomy.png
The Muscular System

Muscles attach to the skeleton (by way of tendons), and do
the work of moving parts of the animal.

Muscles can work only by contracting, pulling - they cannot
push. Therefore, many muscles are in pairs - one to extend
(or straighten) a joint, and the other to flex (or bend) that
joint.

There are three main types of muscle - skeletal muscle,
which is what we usually think of when we think 'muscle', and
which helps the horse walk, trot, gallop, eat, or look around;
smooth, or involuntary, muscle, like the muscles of the
digestive system which push the food through the alimentary
canal; and heart muscle.
The Muscular System
(continued)

The skeletal muscle fibers may be classed as two kinds: slow
twitch and fast twitch.

Draft horses and sprinters tend to have more 'fast twitch'
muscle fibers, which are more powerful in the short term.

Endurance horses and stayers tend to have more 'slow twitch'
muscle fibers, which can work longer.

In order to work efficiently, muscles must be able to relax
between contractions - a muscle that is constantly
contracting without frequent, short breaks to relax will
become tired, stiff, and more prone to injury.

Muscles generally get stronger with work, but overworked
muscles will not be able to repair minor damage quickly
enough, and may be torn, or strained.
The Muscular System
(continued)

In the living body, different muscles are layered over each
other, often two, three or four layers deep.

Therefore, it takes more than a single picture to show many
muscles.

The next two diagrams do not show how the muscles look,
but only their locations relative to the skeleton, and include
many, but by no means all, of the equine muscles.
Muscular
SystemGroup 1
https://share.ehs.uen.org/node/1570
Muscular
SystemGroup 2
https://share.ehs.uen.org/node/1570
The Reproductive System

Horses have a typical mammalian reproductive system.

A stallion has testicles and a penis, which is usually protected
inside the sheath.

A mare has ovaries, a uterus and vagina.

During the breeding season (from early spring till early
autumn) the mare becomes fertile at roughly three-week
intervals.

The several days when she will accept the stallion, she is said
to be "in heat" or “in season” for breeding.
Reproductive
Systems
http://www.google.com/imgres?imgurl=http://www.merckvetmanual.com/media/pet/figures/DDH_mare_reproductive_system.gif&imgr
efurl=http://www.merckvetmanual.com/pethealth/horse_disorders_and_diseases/reproductive_disorders_of_horses/the_gonads_and_gen
ital_tract_of_horses.html&h=412&w=450&tbnid=6n_3Cv2cFVHJM:&zoom=1&docid=P4VLX3zxr72mlM&ei=0HdzVaf7HpfioASUlrfwDA&tbm=isch&ved=0CBwQMygAMAA
http://www.google.com/imgres?imgurl=http://www.merckvetmanual.com/media/pet/figures/DDH_stallion_reproductive_system.gif&imgrefu
rl=http://www.merckvetmanual.com/pethealth/horse_disorders_and_diseases/reproductive_disorders_of_horses/the_gonads_and_genital_tra
ct_of_horses.html&h=637&w=450&tbnid=BLfDZ4jjyAyGPM:&zoom=1&docid=P4VLX3zxr72mlM&ei=0HdzVaf7HpfioASUlrfwDA&tbm=isch&ved=0CB
4QMygCMAI
The Nervous System

The nervous system consists of the central nervous system
(the brain and spinal cord), and the peripheral nervous
system (the nerves in the rest of the body).

Through the nerves to the sensory organs (ears, eyes, nose,
tongue and skin), the horse perceives information about what
is going on around him.

Through the nerves to all the organs and systems of the body,
the horse's brain coordinates all activities, including
breathing, heartbeat, movement, and digestion.

You might consider the nervous system to be the
communications and control department for the body.
Nervous
System
http://www.merckvetmanual.com/media/pet/figures/DDH_horse_nervous_system.gif
The Circulatory System

As do all mammals, horses possess a four-chambered
heart which receives blood from the veins, and pumps
it out into the arteries to keep the entire body
supplied with oxygen and nutrients, and to move out
waste products like carbon dioxide.

Along with the heart and blood vessels, the
circulatory system includes the blood, the lymph
nodes and vessels, and lymph.

The lymph system is part of the immune defenses
which protect the horse from disease.
Circulatory
System
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ca
d=rja&uact=8&ved=0CAcQjRw&url=http%3A%2F%2Fwww.gutenberg.org%2Ffile
s%2F23403%2F23403-h%2F23403h.htm&ei=XXlzVbeVNsTEsAX7voF4&psig=AFQjCNHcf2CZv1jL6wvQJlnjY03RXFwVA&ust=1433717417799709
Circulatory
System—
Heart
http://www.google.com/imgres?imgurl=http://www.vetgo.com/cardio/concepts/images/heart_
labelled_large2.jpg&imgrefurl=http://www.vetgo.com/cardio/concepts/concsect.php?sectionke
y%3D9&h=347&w=346&tbnid=LejoCPiAB3M7EM:&zoom=1&docid=ITyrw76AX2xqEM&ei=RJN0Vc2WLI
a4ogSIvpdI&tbm=isch&ved=0CB8QMygDMAM
Respiratory System




The respiratory system is the breathing apparatus nostrils, larynx, trachea and lungs.
Unlike humans, horses cannot easily breath through their
mouths, but must move all air in and out through their
nostrils.
Like humans, the horse's respiratory system is vulnerable
to colds, coughs, pneumonia and even "emphysema"
(Chronic Obstructive Respiratory Disease - often called
heaves in horses).
Horses must often live in dusty environments, and eat
dusty hay, stressing their lungs. As athletes, horses need
healthy lungs to perform well.
Respiratory
System
https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http%3A%2F%2Ffhotd64476.yuku.
com%2Ftopic%2F49913%2FPics-of-ThroatConformation&ei=Wpp0VeORAYrJtQXopoHoBg&psig=AFQjCNE0YrWgj5OtUaTWfUWOQy2dnfBSbQ&ust=1433791433268204
Systems Activity

Pick three of the systems we discussed

Draw and label a picture of each system
and its components

For each system describe why it is
important to the horse

Post your pictures around the classroom
Questions for Review

Which system is responsible for supporting the body?

Which system is responsible for moving parts of the body?

Which system is responsible for breathing?

Which system is responsible for oxygenating blood?

Which system is responsible for absorbing nutrients from food?
Questions for Review

Which system is responsible for supporting the body?
 Skeletal

System
Which system is responsible for moving parts of the body?
 Muscular

System
Which system is responsible for breathing?
 Respiratory

Which system is responsible for oxygenating blood?
 Circulatory

System
System
Which system is responsible for absorbing nutrients from food?
 Digestive
System
Summary




Just like in humans, the equine body is formed by many
systems working together to ensure health of the animal
Though we covered several systems, there are others we
did not have time to discuss like the excretory, endocrine,
immune, and integumentary system.
In order to fully understand the anatomy and physiology of
the horse, we need a basic understanding of the primary
systems.
If you want to learn more, there are many resources
available online that can help you—we can even dissect a
horse fetus to further study these systems.
References

The Merck Veterinary Manual:
https://www.merckvetmanual.com/mvm/index.html

Overview of Equine Body Systems:
https://share.ehs.uen.org/node/1570

Equine Colic Surgery:
https://www.youtube.com/watch?v=mfysbxvqb40
Texas College and Career Readiness
Standards

English Language Arts: V. Research, B, 1, a-b

Science: VI: Biology, E. 1, F. 1-2

Social Studies: IV. Analysis, Synthesis, and Evaluation of
Information. B, 2-4; V. Effective Communication. A. 1-2.
Developed by the Department of Agricultural Leadership,
Education & Communications,
Texas A&M University
for the Texas Education Agency, Educational Excellence
Project for AFNR
©Texas Education Agency, 2015