“Things that make you go Hmmmm….”

“What happens if you get scared half to death twice?”

CHAPTER 1Introduction to Anatomy & Physiology

Introduction to Anatomy and Physiology

• All the parts of an animal’s body are simply like components to a machine.

• These components include:– Cells

– Tissues

– Organs

– Systems

• As future LVT’s it is your responsibility to adequately understand this machine and how it works in order to effectively care for it.

• We must be able to differentiate “normal” from “abnormal”.

Anatomy and Physiology

• Anatomy-deals with the form and structure of the body and its parts.– What it looks like and where it is located

• Physiology- deals with the function of the body and its parts.– How things work and what they do

Types of Anatomy

• Microscopic Anatomy- anatomy of structures so small that a microscope is required to view them clearly.

• Macroscopic Anatomy (Gross Anatomy)- anatomy that deals with body parts large enough to be seen with the unaided eye such as organs, muscles and bones.

• Regional Anatomy- study of individual areas or “regions” of the body.

• Systemic Anatomy- study of individual systems of the body.

• There may be overlap in some of these areas.

Main Body Systems• Skeletal- bones and joints.• Integumentary- skin, hair, nails and hooves.• Nervous- Central Nervous System (CNS) and

peripheral nerves.• Cardiovascular-heart and blood vessels.• Respiratory- lungs and air passageways.• Digestive- Gastrointestinal (GI) tube and

accessory digestive organs.• Muscular- Skeletal, cardiac, and smooth muscle.• Sensory- Organs of general and special sense• Endocrine-Endocrine glands and hormones• Urinary-Kidneys, ureters, urinary bladder, and

urethra.• Reproductive-Male and female reproductive

structures.

Terminology

• Why do we need specific anatomical terminology?

• Anatomical terms are based on imaginary slices, called planes through the animal body that can be used as points or areas of reference.

• Anatomical terms are also based on directional terms that have opposite meanings of one another.

Anatomical Planes of Reference

• Four anatomical planes of reference:– 1. Sagittal plane- a plane that runs the length of the

body and divides it into left and right parts that are not necessarily equal halves.

• 2. Median plane (midsaggital plane)- a special type of sagittal plane that runs down the center of the body lengthwise and divides it into equal left and right halves.

– 3. Transverse plane- A plane across the body that divides it into cranial (head-end) and caudal (tail-end) parts that are not necessarily equal.

– 4. Dorsal plane- A plane at right angles to the sagittal and transverse planes. It divides the body into dorsal (toward the back) and ventral (toward the belly) parts that are not necessarily equal.

Directional Terms

• Help to accurately and clearly describe body structures regardless of position of animal’s body.

• Terms generally occur in pairs and have opposite meanings and are used to describe relative positions of body parts.

Directional Terms

Direction

Individual’s left

Individual’s right

Toward the head end of the body

Toward the tip of the nose (head only)

Toward the tail end of the body

Toward the back

Toward the belly

Toward the median plane

Away from the median plane

Toward the center (whole body or part)

Toward the surface (whole body or part)

Toward the body (extremity)

Away from the body (extremity)

“Back” of forelimb distal to carpus

“Back” of hindlimb distal to tarsus

“Front” of forelimb & hindlimb

distal to carpus & tarsus

Domestic Animal

Left

Right

Cranial

Rostral

Caudal

Dorsal

Ventral

Medial

Lateral

Deep (internal)

Superficial

Proximal

Distal

Palmar

Plantar

Dorsal

Directional Terms Continued

• Left and right refer to animal’s left and right.

• Cranial and caudal refer to the two ends of the animal. – Can state something is cranial or caudal

relative to something else.

• Rostral means towards the nose and only describes positions or directions on the head.

• Dorsal and ventral refer to up and down or towards the back and towards the belly. (humans use posterior and anterior).

More Directional Terms

• Medial and lateral refer to towards the midline or away from the midline– What is midline plane called?

• Deep and superficial refer to the position of something relative to the center or surface of the body. – Deep-toward the center of the body (internal)

– Superficial- toward the surface of the body or a body part (external).

• Proximal and distal describe positions only on extremities relative to other parts of the body. – Proximal-toward the body

– Distal- away from the body

Special Directional terms

• Palmar- back surface of the carpus (wrist).• Plantar- back surface of the hind limb

distal to the tarsus (ankle).

Describe these pictures

And again

Front paw of a dogRear paw of a dog

One more time

General Plan of the Animal Body• Bilateral Symmetry- idea that left and right halves of animal’s body

are essentially mirror images of one another. – Where does this work?– Where does this not work?

• Body Cavities- Animal’s have two main cavities (spaces).– 1. Dorsal cavity- Contains brain and spinal cord (CNS)

• Subdivides into cranial and spinal cavities– 2. Ventral cavity- contains most of the soft organs (viscera) of the

body.• Subdivides into thoracic and abdominal cavities• What is visceral pleura? What is visceral peritoneum?• What is parietal pleura? What is parietal peritoneum?

• Levels of Organization that make up the body– Cells– Tissues– Organs– Systems

Levels of Organization Continued

• Cells- basic functional units of all life.– Smallest subdivisions of the body that are capable of life– Generally are specialized in nature

• Tissues- when specialized cells group together to do the same job.– 4 basic tissue types:

• 1. Epithelial-cells that cover body surfaces• 2. Connective-holds body together and gives it support

– Can you give an example?• 3. Muscle- moves body inside and out

– Skeletal– Cardiac– Smooth

• 4. Nervous- transmits information around the body and controls body functions.

• Organs- groups of tissue that work together for a common purpose

• Systems-groups of organs that have a common set of activities

Health

• The state of normal anatomy and physiology.

• Maintaining health may be a difficult and complicated process.

• All structures and functions in the body are interrelated to produce optimal health.

Homeostasis

• The maintenance of a dynamic equilibrium in the body.– Active balance of all of the structures, systems

and functions of the body– All parts are inter-related and balanced– Blood pressure, acid-base balance, oxygen

levels