Strand 2.2 Body Systems — Integrated Animal Anatomy & Physiology

External Anatomy

The set of visible body regions used to describe an animal’s structure, movement, and condition.

Directional Terms

Terms like dorsal, ventral, cranial, and caudal used to describe body orientation.

Dorsal

Toward the back or spine of an animal.

Ventral

Toward the belly of an animal.

Cranial

Toward the head.

Caudal

Toward the tail.

Medial

Toward the midline of the body.

Lateral

Away from the midline of the body.

Proximal

Closer to the body.

Distal

Farther from the body.

Muzzle/Snout

Used by cattle, horses, and pigs for food grasping and sensory roles.

Beak

The feeding and grooming structure in birds, shaped to match diet.

Nares

Nostrils used for air intake and smell.

Withers

The top of the shoulders in horses and dogs; important for height measurement.

Barrel

The ribcage region in horses, relating to lung capacity and body condition.

Hoof

A structure in horses, cattle, sheep, and goats that supports weight and protects the limb.

Claw

Used by dogs and cats for traction, digging, and defense.

Dewclaw

A vestigial digit in dogs and some livestock; can snag and cause injuries.

Alveoli

Tiny sacs in the lungs where gas exchange occurs.

Monogastric

Refers to animals like pigs, dogs, and humans with a single-chambered stomach.

Ruminant

Animals like cattle and sheep with a four-compartment stomach used for digesting fibrous materials.

Nephron

The functional unit of the kidney responsible for filtering blood and forming urine.

Epidermis

The outer protective layer of skin.

Dermis

The connective tissue layer beneath the epidermis containing blood vessels and nerves.

Thyroid Gland

Endocrine gland that influences metabolic rate and growth.

Antibodies

Proteins produced by B cells as part of the adaptive immune response.

Adaptive Immunity

The part of the immune system that is specific and has memory against pathogens.

Innate Immunity

The fast, non-specific immune response that includes physical barriers and inflammation.

Feedback Loops

Mechanisms that regulate hormone levels in the endocrine system, either positively or negatively.

Ureter

The tube that carries urine from the kidney to the bladder.

Hormones

Chemical messengers released into the bloodstream by endocrine glands.