Unit 3: Anatomy & Physiology

Unit 3: Anatomy & Physiology

Veterinary Medical Applications I

Directional Terminology


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


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.


Anatomical Terms


ANTERIOR

• The front of the animal


POSTERIOR

• The rear of the animal


CRANIAL

• Towards the head


CAUDAL

• Towards the tail


DORSAL

• Along the back or uppermost surface


VENTRAL

• Along the belly or undermost surface


PROXIMAL

• Part of the limb closest to the body


DISTAL

• Part of the limb furthest from the body


Three-Dimension Planes


FRONTAL PLANE

• Body plane that divides the animal into dorsal and ventral parts


MEDIAN PLANE

• Body plane that divides the animal into equal, symmetrical right and left halves.


SAGITTAL PLANE

• Any body plane that is parallel to the median plane.


TRANSVERSE PLANE

• Body plane that divides the animal into cranial and caudal parts.


SUPERFICIAL

• Closer to the surface


DEEP

• Further from the surface– Example: superficial and deep flexor tendons


Skeletal System


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


Appendicular: ForelimbScapula – “shoulder blade” attached with muscleClavicle – the cat is the only domestic animal with a clavicle!Humerus – forms the upper armUlna – forms the elbow joint, fused with the radius in herbivoresRadius – forms the forearmCarpus – commonly called the “knee” in horses, the “wrist” in dogs and humansMetacarpals – commonly called the cannon region of the forelimb.Number depends on species:

a) Humans: 5b) Horses: 1 plus 2 accessory metacarpals, called “splint bones”c) Dogs and cats: 4 plus the dewclawd) Cattle: 1 that splits at bottom into a cloven hoof and two dewclawse) Pigs: 4 (2 toes and 2 dewclaws)


Appendicular: Forelimb Continued

Proximal phalanx (P1) – bones of the finger,hoof, and clawIntermediate phalanx (P2)Distal phalanx (P3) – the coffin bone inhorsesProximal sesamoids – tucked in behind P1Distal sesamoid – tucked in underneath P3


Appendicular: HindlimbPelvis

a) Tuber coxae – part of pelvis that forms the “point of hip”b) Ischiatic tuberosity- part of pelvis that forms the “seat bones”

FemurPatella – forms the “stifle” joint in horses, sometimes called the “knee” indogs, equivalent to the human kneeTibia – main bone of the gaskin of the horseFibula – fused with the tibia & consideredvestigial in herbivoresTarsus – commonly called the “hock”, equivalent to the human “ankle”. Metatarsal – cannon region in the hind limb.

Number depends on species.


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.


Periosteum

Epiphysis

Bone marrow

Medullary cavity

Metaphysis

Endosteum

Diaphysis


Bone Anatomy

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Fissured ComminutedTransverseGreenstick


Classifications of Fractures

Muscular System


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 beatingof the heart, appears striated under a microscope.• Smooth muscle – responsible for all other

involuntary movement, such as breathing, digestion, peristalsis, blinking, etc.


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


Muscle Function

• All muscles can do is CONTRACT or RELAX, sothey generally work in pairs. For any particularaction, 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.


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MasseterBrachiocephalicus

Biceps femoris

Gastrocnemius

Semitendinous

Intercostal

Triceps brachii

Deltoid

Gluteals

Trapezius

Latissimus dorsi

External abdominal oblique

Pectorals

Major Muscles


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!)


Nervous System


Axon – sends impulses away from cellBrain – major organ of nervous system; contained within the skullBrainstem – connects the cerebrum with the spinal cord; contains the Medulla oblongataCentral nervous system – contains brain and spinal cordCerebellum – coordinates movement and muscle activity, balanceCerebrum – largest portion of brain; responsible for receiving and storing information and signaling for voluntary movement

Vocabulary

Connecting neuron – carries impulses from one neuron to anotherDendrites – branch-like; receive impulsesHomeostasis – state of balance of the physiologic systems within the bodyImpulse – electrical signal that is transmitted through nervous tissueMedulla 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 layersMotor neuron – carries impulses from the brain towards the muscles and glands

Nerve – term for one or more bundles of nerve cellsNeuron – nerve cellsNeurotransmitter – chemical substance that allows impulses to travelParasympathetic nervous system – maintains and restores normal body functionPeripheral nervous system – consists of all nerves that lead to and from the spinal cord and brain, known as cranial and spinal nervesSensory neuron – carries impulses towards the brain and spinal cordSoma – cell body that contains the nucleusSpinal 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

Cell body (soma)

Synapse

Myelin sheath

Dendrite

Axon

http://safari.pisd.edu/?a=175072&s=00:00:00:00&e=00:00:49:00&d=25344AA




Parts of a Neuron

1. Cell Body – often called the soma. Contains the cell nucleus2. Dendrite – branch-like, receives impulses3. Axon – sends impulses away from the cell4. Synapse – space in between neurons; contains a chemical substance called a neurotransmitter that helps impulses travel5. Myelin – protective sheath around the neuron

Central Nervous SystemCentral Nervous System – consists of brain and spinal cord.1. Brain – major organ of the nervous system.a. Meninges – three-layered protective covering of the brain.b. Cerebrum – largest part of the brain. It has four lobes that receive and store

information And are responsible for giving signals for voluntary movementc. 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 medulla oblongata.

Parts of the Brain

Meninges

Medulla oblongataBrain stem

Cerebrum

Cerebellum

Hypothalamus

Thalamus

Spinal cord

Pituitary gland

• 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


Alveoli – grape-like clusters at ends of bronchioles; where exchange of oxygen and carbon dioxide gases occurApnea – not breathingAsphyxiation – suffocation; blockage of airflow that results in a lack of oxygenBradypnea – abnormally slow respiratory rate Bronchi – paired terminal branches of the trachea contained within the lungs; singular: bronchus

Vocabulary

Bronchial tree – term that describes how bronchi get continually smaller, like a tree branchBronchioles – smallest branches of the bronchial treeCilia – tiny hairs inside nostrils that help to filter airDiaphragm – Muscle located below the lungs; contraction causes the lungs to draw in a breath

Dyspnea – difficult breathingEpiglottis – flap that covers the larynx during swallowingExhalation – release of a breathInhalation – drawing in of a breathLarynx – ‘voice box’ that contains vocal cords

Lungs – paired major organs of respiration that contain bronchi and are divided into clearly defined lobesMucous membrane – lining of respiratory tract that secretes mucusMucus – slimy secretion that warms, moistens, and filters air

Pharynx – common passageway for both the respiratory and digestive systemsRespiration – exchange of oxygen and carbon dioxide gases with cellsTachypnea – abnormally fast respiratory rateTrachea – windpipe; has distinct rings of cartilage

Unit 3: Anatomy & Physiology

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