Unit 3: Anatomy & Physiology
Veterinary Medical Applications I
Directional Terminology
Unit 3: Anatomy & Physiology
Introduction
• It is very important for the veterinary assistant
to be familiar with basic anatomical
terminology.
• This knowledge helps to better understand
medical conditions and treatments, follow
instructions from the veterinarian, perform
basic veterinary medical procedures
Unit 3: Anatomy & Physiology
Anatomical Terminology
• Being familiar with anatomical terminology is
important, and the terms used here will be
repeated throughout this and other units.
• These terms will be used in the description of
bones, the names of muscles, as well as in the
description of clinical cases.
Unit 3: Anatomy & Physiology
Anatomical Terms
Unit 3: Anatomy & Physiology
ANTERIOR
• The front of the animal
Unit 3: Anatomy & Physiology
POSTERIOR
• The rear of the animal
Unit 3: Anatomy & Physiology
CRANIAL
• Towards the head
Unit 3: Anatomy & Physiology
CAUDAL
• Towards the tail
Unit 3: Anatomy & Physiology
DORSAL
• Along the back or uppermost surface
Unit 3: Anatomy & Physiology
VENTRAL
• Along the belly or undermost surface
Unit 3: Anatomy & Physiology
PROXIMAL
• Part of the limb closest to the body
Unit 3: Anatomy & Physiology
DISTAL
• Part of the limb furthest from the body
Unit 3: Anatomy & Physiology
Three-Dimension Planes
Unit 3: Anatomy & Physiology
FRONTAL PLANE
• Body plane that divides the animal into dorsal
and ventral parts
Unit 3: Anatomy & Physiology
MEDIAN PLANE
• Body plane that divides the animal into equal,
symmetrical right and left halves.
Unit 3: Anatomy & Physiology
SAGITTAL PLANE
• Any body plane that is parallel to the median
plane.
Unit 3: Anatomy & Physiology
TRANSVERSE PLANE
• Body plane that divides the animal into cranial
and caudal parts.
Unit 3: Anatomy & Physiology
SUPERFICIAL
• Closer to the surface
Unit 3: Anatomy & Physiology
DEEP
• Further from the surface
– Example: superficial and deep flexor tendons
Unit 3: Anatomy & Physiology
Skeletal System
Unit 3: Anatomy & Physiology
Skeletal System
• The skeleton is a framework of structures,
made of bones and cartilage that support and
protect the body.
• Axial Skeleton: includes the skull, vertebrae,
ribs, and sternum.
• Appendicular Skeleton – the fore and hind
limbs
Unit 3: Anatomy & Physiology
Unit 3: Anatomy & Physiology
Appendicular: Forelimb
Scapula – “shoulder blade” attached with muscle
Clavicle – the cat is the only domestic animal with a clavicle!
Humerus – forms the upper arm
Ulna – forms the elbow joint, fused with the radius in herbivores
Radius – forms the forearm
Carpus – commonly called the “knee” in horses, the “wrist” in dogs and
humans
Metacarpals – commonly called the cannon region of the forelimb.
Number depends on species:
a) Humans: 5
b) Horses: 1 plus 2 accessory metacarpals, called “splint bones”
c) Dogs and cats: 4 plus the dewclaw
d) Cattle: 1 that splits at bottom into a cloven hoof and two
dewclaws
e) Pigs: 4 (2 toes and 2 dewclaws)
Unit 3: Anatomy & Physiology
Appendicular: Forelimb Continued
Proximal phalanx (P1) – bones of the finger,
hoof, and claw
Intermediate phalanx (P2)
Distal phalanx (P3) – the coffin bone in
horses
Proximal sesamoids – tucked in behind P1
Distal sesamoid – tucked in underneath P3
Unit 3: Anatomy & Physiology
Appendicular: Hindlimb
Pelvis
a) Tuber coxae – part of pelvis that forms the “point of hip”
b) Ischiatic tuberosity- part of pelvis that forms the “seat bones”
Femur
Patella – forms the “stifle” joint in horses, sometimes called the “knee” in
dogs, equivalent to the human knee
Tibia – main bone of the gaskin of the horse
Fibula – fused with the tibia & considered
vestigial in herbivores
Tarsus – commonly called the “hock”, equivalent to the human “ankle”.
Metatarsal – cannon region in the hind limb.
Number depends on species.
Unit 3: Anatomy & Physiology
Classification of Bones
• Short bone – cube shaped, i.e. carpus and tarsus
• Flat bone – plate of bone, i.e. scapula, rib, skull
• Irregular bone – complex shaped, i.e. vertebrae
• Sesamoid – small, seed-shaped bone,
i.e. proximal and distal sesamoids, patella
• Long bone – bone is longer that it is wide,
i.e.femur, tibia, humerus, etc.
Unit 3: Anatomy & Physiology
Bone Anatomy
Epiphysis
Diaphysis
Periosteum
Medullary cavity
Endosteum
Bone marrow
Metaphysis
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Classifications of Fractures
Fissured
Unit 3: Anatomy & Physiology
Greenstick
Transverse
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Comminuted
Muscular System
Unit 3: Anatomy & Physiology
Types of Muscle
• Skeletal muscle – allows for all voluntary
movement, appears to be striated when looked
at under a microscope.
• Cardiac muscle – controls the involuntary beating
of the heart, appears striated under a microscope.
• Smooth muscle – responsible for all other
involuntary movement, such as breathing,
digestion, peristalsis, blinking, etc.
Unit 3: Anatomy & Physiology
Muscle Movement
• Ambulation: moving from one place to
another
• Abduction: moving away from the median
plane
• Adduction: moving towards the median plane
• Flexion: moving the distal part of the limb
towards the body
• Extension: moving the distal part of the limb
away from the body
Unit 3: Anatomy & Physiology
Muscle Function
• All muscles can do is CONTRACT or RELAX, so
they generally work in pairs. For any particular
action, the muscles involved can be classified as:
• Agonist – prime mover of a joint
• Antagonist – opposes movement of the agonist
• Ex: for elbow flexion, the agonist is the bicep, and
the antagonist is the tricep. For elbow extension,
the agonist is the tricep, and the antagonist is the
bicep.
Unit 3: Anatomy & Physiology
Major Muscles
Brachiocephalicus
Masseter
Trapezius
Latissimus
dorsi
External abdominal
oblique
Gluteals
Pectorals
Semitendinous
Deltoid
Triceps
brachii
Unit 3: Anatomy & Physiology
Gastrocnemius
Intercostal
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Biceps
femoris
Description/Function of Muscles
• Masseter – superficial muscle of the cheek
• Trapezius – superficial triangular muscle of the shoulder
• Latissimus dorsi – long, superficial, dorsal muscle that attaches the
humerus to the lumbar region of the back
• Abdominal obliques – large flat muscles that support digestive and
reproductive organs
• Gluteals – large muscle of the upper hindquarters
• Biceps femoris – lateral superficial muscle, one of three which
forms the “hamstrings”
• Biceps brachii – primary flexor of the elbow joint
• Triceps brachii – primary extensor of the elbow joint
• Pectorals – primary adductors of the forelimbs
• Serratus ventralis – attaches forelimb to trunk (no collarbone!)
Unit 3: Anatomy & Physiology
Nervous System
Unit 3: Anatomy & Physiology
Vocabulary
Axon – sends impulses away from cell
Brain – major organ of nervous system; contained
within the skull
Brainstem – connects the cerebrum with the spinal
cord; contains the Medulla oblongata
Central nervous system – contains brain and spinal
cord
Cerebellum – coordinates movement and muscle
activity, balance
Cerebrum – largest portion of brain; responsible for
receiving and storing information and signaling for
voluntary movement
Connecting neuron – carries impulses from one neuron
to another
Dendrites – branch-like; receive impulses
Homeostasis – state of balance of the physiologic
systems within the body
Impulse – electrical signal that is transmitted through
nervous tissue
Medulla oblongata – part of the brain responsible for
all life functions including: heart rate, breathing, and
reflex actions (coughing, sneezing, swallowing, and
vomiting)
Meninges – protective layer covering the brain; has
three layers
Motor neuron – carries impulses from the brain
towards the muscles and glands
Nerve – term for one or more bundles of nerve cells
Neuron – nerve cells
Neurotransmitter – chemical substance that allows impulses to
travel
Parasympathetic nervous system – maintains and restores
normal body function
Peripheral nervous system – consists of all nerves that lead to
and from the spinal cord and brain, known as cranial and spinal
nerves
Sensory neuron – carries impulses towards the brain and spinal
cord
Soma – cell body that contains the nucleus
Spinal cord – pathway for all impulses going to and from the
brain,
Sympathetic nervous system – responsible for stress and
emergency responses; “fight or flight”
Synapse – space between neurons that contains a
neurotransmitter
Functions of the Nervous System
• Detects and processes information and
formulates responses; coordinates and
controls all bodily activity.
• The nervous system sends and receives
impulses –electrical signals that travel though
the nervous system and provide information
to the brain.
Types of Neurons
Sensory neurons – carry impulses towards the
brain and spinal cord.
Connecting neurons – carry impulses from one
neuron to another.
Motor neurons – carry impulses away from the
brain and spinal cord to the body.
Parts of a Neuron
Dendrite
Cell body
(soma)
Myelin sheath
Axon
Synapse
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Parts of a Neuron
1. Cell Body – often called the soma. Contains
the cell nucleus
2. Dendrite – branch-like, receives impulses
3. Axon – sends impulses away from the cell
4. Synapse – space in between neurons;
contains a chemical substance called a
neurotransmitter that helps impulses travel
5. Myelin – protective sheath around the neuron
Central Nervous System
Central Nervous System – consists of brain and spinal cord.
1. Brain – major organ of the nervous system.
a.
b.
Meninges – three-layered protective covering of the brain.
Cerebrum – largest part of the brain. It has four lobes that receive and
store information
And are responsible for giving signals for voluntary
movement
c. Cerebellum – coordinates all movement, muscle activity, and balance.
d. Brainstem – connects the brain to the spinal cord and contains the
medulla oblongata.
e. Medulla oblongata - dictates all life functions including: heart rate,
breathing, and reflex actions.
f. Thalamus – a central relay system for all nerve impulses except smell. It
receives the impulses and then directs them to the proper part of
the brain.
g. Hypothalamus – serves as a link between the nervous system and the
endocrine
system.
h. Pituitary gland – secretes hormones important for reproduction and
growth.
2. Spinal cord – pathway for all impulses going to and from the brain. Connects to the
Parts of the Brain
Meninges
Cerebrum
Cerebellum
Thalamus
Spinal cord
Hypothalamus
Pituitary
gland
Brain stem
Medulla oblongata
• Peripheral Nervous System – consists of nerves
that relay information to and from the spinal
cord.
• Sympathetic Nervous System – Responsible for
emergency and stress responses: “fight or flight”.
• Parasympathetic Nervous System – Seeks to
maintain and restore normal body function, often
called Homeostasis: a state of balance of the
physiologic systems within the body
Respiratory System
Unit 3: Anatomy & Physiology
Vocabulary
Alveoli – grape-like clusters at ends of bronchioles;
where exchange of oxygen and carbon dioxide gases
occur
Apnea – not breathing
Asphyxiation – suffocation; blockage of airflow that
results in a lack of oxygen
Bradypnea – abnormally slow respiratory rate
Bronchi – paired terminal branches of the trachea
contained within the lungs; singular: bronchus
Bronchial tree – term that describes how
bronchi get continually smaller, like a tree
branch
Bronchioles – smallest branches of the bronchial
tree
Cilia – tiny hairs inside nostrils that help to filter
air
Diaphragm – Muscle located below the lungs;
contraction causes the lungs to draw in a breath
Dyspnea – difficult breathing
Epiglottis – flap that covers the larynx during
swallowing
Exhalation – release of a breath
Inhalation – drawing in of a breath
Larynx – ‘voice box’ that contains vocal cords
Lungs – paired major organs of respiration that
contain bronchi and are divided into clearly
defined lobes
Mucous membrane – lining of respiratory tract
that secretes mucus
Mucus – slimy secretion that warms, moistens,
and filters air
Pharynx – common passageway for both the
respiratory and digestive systems
Respiration – exchange of oxygen and carbon
dioxide gases with cells
Tachypnea – abnormally fast respiratory rate
Trachea – windpipe; has distinct rings of
cartilage