Animal Organ Systems
Anatomy and Physiology
Fundamentals of Life
All living things are made up of cells.
 Cells are the most basic structure of life.
 Cells need oxygen, food/energy, and
water to survive.
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Natural Hierarchy
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Cells are the most basic and simple.
Cells that are all alike work together to form
tissues which perform tasks.
Tissues that are alike work together to form
organs which complete jobs.
Organs work together in organ systems to
carry out processes.
Organ systems work together to support the
life of an organism.
How do we study animals?
We look at the outside of them – the
outer physical structures.
 We look inside of dead animals – the
internal physical structures.
 We look at the tissues under a
microscope – microscopic structures.
 We study the chemical reactions
between cells, tissues, and organs.
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Anatomy
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The study of the form, shape, and
appearance of an animal – its structures
both internal and external.
Gross anatomy is the study of the
structures – internal and external – that we
can see with the naked eye.
 Microscopic anatomy is the structures that
can only be seen under magnification
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Physiology
The study of the functions of the cells,
tissues, and organs of the animal.
 Biochemistry
 How cells, tissues and organs work
together to complete a task…digestion.
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Why study anatomy and physiology?
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Efficient production of livestock requires
understanding the anatomy and
physiology related to Production.
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Production is muscle gain, milk or egg production,
and hair or wool production.
Raising animals requires an
understanding of the requires needed for
animal wellbeing.
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Animal wellbeing is caring for animals so that their
basic needs are met and they do not suffer.
Mammals vs Non-mammals
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Most of our livestock are mammals.
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i.e. – vertebrate that has hair, gives birth to
live young, produces milk, & maintains
constant body temperature.
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Cattle, horses, pigs, goats & sheep, etc.
Exceptions are poultry & aquacrops.
Poultry – birds – ducks, chickens, turkeys, etc.
 Aquacrops – fish, shrimp, etc.
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Organ Systems
Skeletal
 Muscular
 Nervous
 Circulatory
 Respiratory
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Excretory
 Digestive
 Endocrine
 Integumentary
 Reproductive
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Skeletal
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Bones
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50% water, 26% minerals (Ca & P),
20% protein, 4% fat
Core is soft and spongy – called marrow
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Cartilage
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Marrow makes new red blood cells for body.
Soft, tough tissue found between bones
that cushions joints
Ligaments
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Long stretchy tissue that holds joints
together
Skeletal
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Gives structure and support
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Protects internal organs
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Makes locomotion/movement possible
Skeletal - Joints
Skeletal - Skull
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Skull is made up of several fused bones
Skeletal - Spine
The spine is made up of many vertebrae
and cartilage disks
 5 types of vertebrae
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Cervical – neck
 Thoracic – body
 Lumbar – lower back
 Sacral – around hip
 Coccygeal - tail
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Muscular
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Muscles
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Fibrous cells that are design to contract and relax in
pairs
Voluntary – under the organisms conscious control –
triceps
Involuntary – automatically move to regulate body
functions – heart and diaphragm
Tendons
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Long, thin, stretchy tissues that attach muscles to
bones.
Muscles pull against bone when they contract which
causes movement.
Muscular
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Primary function is movement.
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External & internal
Also protect delicate organs
 Muscles make up about half our
livestock animals’ weight.
 Composed mostly of protein.
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Muscular
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Three types of muscles
Skeletal – meat – bicep – voluntary
 Cardiac – heart – involuntary
 Smooth – digestive system - involuntary
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Skeletal
Cardiac
Smooth
A=Rhomboideus capitis
B=Splenius
C=Levator scapulae ventralis
D=Supraspinatus
E=Infraspinatus
F=Teres major
G=Serratus dorsalis
H=Longissimus dorsi
I=Multifidae spinae
J=Clavotrapezius
K=Clavobrachialis
L=Acromiodeltoid
M=Spinodeltoid
N=Acromiotrapezius
O=Spinotrapezius
P=Spinalis dorsalis
Q=Latissimus dorsi
R=Rhomboideus
Nervous
Uses electrical impulses to send
messages from brain throughout body.
 Controls activity, learning, memory
 Central Nervous System and Peripheral
Nervous System
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Nervous
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Brain
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Soft tissues that
coordinates all
aspects of animal
function
Spinal Cord
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Main “highway” for
nerve impulses to
travel from brain to
rest of body
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Nerves
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Branch out and reach
rest of body
Sensory organs
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Vision
Olfactory
Touch
Taste
Auditory
Nervous - Brain
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Bain
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Cerebrum – controls voluntary movement
and thought
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Cerebellum – coordination of animal’s
movement
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Kicking, biting, vocals, licking, etc
Walking
Brain Stem – most of the functions to
maintain life
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Body temp, breathing, digestion, heart beat
Brain Stem
Cerebrum
Cerebellum
Nervous – Cranial Nerves
Number Nerve
Sensory Funct
Motor Function
1
Olfactory
Smell
2
Optic
Vision
3
Oculomotor
Position of eye
Move eye, constrict pupil, focus
4
Trochlear
Position of eye
Move eye
5
Trigeminal
Sense in face & teeth
Chewing
6
Abducens
Position of eye
Move eye
7
Facial
Taste buds
Blinking, facial expression
8
Auditory
Hearing & balance
9
Glossopharyngeal
Taste buds
10
Vagus
Sensory of internal organs
11
Spinal accessory
Muscles of shoulder
Move neck and shoulders
12
Hypoglossal
Muscles of tongue
Move tongue
Swallowing
Nervous – Cranial Nerves
Nervous - Sight
Nervous – Touch
Circulatory
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Heart
Technically a muscle
 Pumps blood with 4 chambers and 2 valves
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Arteries
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Carry oxygen rich blood from lungs and heart
to tissues
Veins
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Carry blood back from tissues to lungs and
heart.
Circulatory – Heart - exterior
Circulatory – Heart - interior
Circulation – the flow of blood
Circulatory – Arteries and Veins
Aorta
Vena Carva
Circulatory
Blood
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white blood cells
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Neutrophil
Monocyte
Lymphocyte
Eosinophil
Basophil
 Fights pathogens
Plasma
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Liquid part of blood –
55% of volume
red blood cells
Erythrocytes
 Carries O2 and
carbohydrates
(glucose)
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Platelets
Thrombocytes
 Makes blood clot
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Circulatory - Blood
Circulatory – Stained blood smears
Basophil
Erythrocytes
Eosinophil
Nuetrophil
Thrombocyte
Lymphocyte
Monocyte
Circulatory
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Also includes the Lymph Glands
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Secrete disease fighting materials
Moves materials throughout the body
Respiratory
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Nasal and Sinus Passages
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Pharynx & Larynx
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External opening of the body and passageways
Pharynx connects the esophagus and trachea
Larynx is the “voice box”
Trachea
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Wind pipe that connects nasal passages with
bronchi
Respiratory
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Bronchus
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Bronchioles
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Smaller tubes that branch off of bronchi
Alveoli
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Tube that branch off of the trachea and carry air to
lungs
Small sacks where gas exchange occurs
Lungs
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“bags” that expand and contract to bring in fresh air
and expel old air
Respiratory
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Function is to bring oxygen
into the body and expel
carbon dioxide.
 Exchange of gasses
happens inside the lungs in
the alveoli.
 Lungs expand and contract
due to the movement of the
diaphragm.
Excretory
Also referred to as the Renal System.
 Kidneys
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Remove waste materials from blood
 Nephrons filter out wastes (urine)
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Bladder
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Holds urine
Ureters
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Found in the Medulla and Cortex of kidney
Connect bladder to urethra
Urethra
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Empties urine to the exterior of the animal
Digestive
Large and varied system
 Breaks down food into usable energy
 Removes unusable food from body
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Digestion
Monogastric – 1 stomach – can’t digest
cellulose (fiber) – pigs and humans
 Ruminant – 4 stomachs – polygastric –
digest cellulose, produce own B vitamins
and proteins – cows and sheep
 Pseudo-ruminant - have 1 stomach, but
have enlarged cecum that digests
cellulose – horses and rabbits
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Digestion - Monogastric
Moutn
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Prehension – gathering food – teeth, lips,
tongue
Mastication – Chewing – break food into
smaller pieces for swallowing – teeth and
saliva
Digestion - Teeth
Digestion - Monogastric
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Esophagus – transport tube to stomach –
muscular contractions move food down
Digestion - Monogastric
Stomach
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conditions – pH
of 2, churning
and contracting
to mix and grind
food
ingredients –
food, HCl,
enzymes
Digestion - Monogastric
Small intestine
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major site of nutrient absorption
 Functions – villi absorb nutrients that have
been broken down – minerals, vitamins,
amino acids,
Fatty acids,
simple sugars
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Glands –
gallbladder secretes
bile used for lipid
breakdown;
Pancreas secretes
enzymes for protein
and carbohydrate
breakdown
Digestion - Monogastric
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Large intestine – colon
 accumulates wastes
 absorbs water
Rectum and Anus
Digestion - Monogastric
Cecum
Rectum
Anus
Esophagus
Large
intestine
Small intestine
Digestion - Ruminant
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Mouth
 Prehension – cow tongue is very long
 Mastication – graze rapidly, and don’t
chew much 1st time
Esophagus – liquids to the reticulum
and solids to the rumen
Rumen – very large compartment
Digestion - Ruminant
Regurgitation – when rumen full, force
contents back up to re-chew
 Rumination
 re-mastication of cud or bolus
 Bolus – ball of grass
 Adds saliva to food
 Esophagus – re-swallow food
 Reticulum – honeycomb
Digestion - Ruminant
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Rumen
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fermentation vat
30 gal or more
contains microbes that break down the
cellulose
pH of 6.5 – 7 for microbes
releases methane – belch
creates B vitamins and proteins from
amino acids
also contains papalli that absorb nutrients
released by microbes
Digestion - Ruminant
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Omasum – filter for large particles –
grinds them down
Abomasum – like the monogastric
stomach – acidic
Small intestine – same as monogastric
Large intestine – same as monogastric
Rectum and anus
Abomasum
Reticulum
Rumen
Omasum
Digestion - Ruminant
Rumen
Rectum
Large
intestine
Omasum
Anus
Cecum
Abomasum Reticulum
Small intestine
Digestion – Pseudo-Ruminant
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Mouth
prehension
 Mastication
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Esophagus
 Stomach
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same as monogastric
 too small in horses and inactive – doesn’t
break down cellulose
 require frequent smaller meals
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Digestion – Pseudo-Ruminant
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Small intestine – absorption of nutrients
– same as monogastric
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**Still has not digested the cellulose – large
amount
Cecum
 enlarged area between small and
large intestine
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contains microbes that break down cellulose
like rumen
Digestion – Pseudo-Ruminant
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Large colon – absorbs nutrients
released by cecum
Small colon – absorbs water and
collects waste
Rectum and Anus
Digestion – Pseudo-Ruminant
Small
colon
Large
colon
Rectum
Esophagus
Anus
Cecum
Small
intesine
Endocrine
Ductless glands in the body
 hypothalamus, pituitary, pancreas, liver,
thyroid, adrenal
 Secrete hormones that chemically
regulate certain functions of the body
 Play a large role in reproduction,
digestion, growth, etc.
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Integumentary
Skin, hair, hooves, horns, etc
 Keeps out pathogens, regulates body
temp, gives shape and color, protects
internal organs
 System made almost entirely out of protein
 Animal skin is called the hide
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Most animal hides made into leather
Reproductive System
Most complex system in animals
 Allows for reproduction of animals and
the continuation of the species
 Different structures between male and
female
 Most animals fundamentally have the
same system, just varies in structure
between species.
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