animal anatomy exam directional terms tissue

Anatomy

Focus on the form, shape and physical structure of animal organisms

Physiology

The study of the functions of living organisms and their parts

Microscopic Anatomy

Focuses on structures that can only be seen with a microscope (e.g., cells and tissues).

Macroscopic (Gross) Anatomy

Focuses on body structures seen with the unaided eye (e.g., organs, muscles, and bones).

Regional Anatomy

Examines all structures, tissue layers, vessels, and organs within a specific individual region of the body (e.g., the head, neck, or abdoment).

Systemic Anatomy

Focuses on individual body systems (e.g., cardiovascular, respiratory, or skeletal system

Anatomical planes of reference

Sagittal Plane, Median Plane, Transverse Plane, Dorsal Plane

Sagittal Plane

A plane running lengthwise through the body, dividing it into unequal right and left parts.

Median Plane

Runs directly along the midline, dividing the body into equal right and left halves.

Transverse Plane

A plane across the body at right angles to its long axis, dividing it into cranial (head end) and caudal (tail end) portions

Dorsal Plane

A plane dividing the body into dorsal (back) and ventral (belly) portions

Directional Terms Right and Left

Refers strictly to the animals own left and right sides, not the viewer perspective

Cranial

Towards the head (cranium)

Caudal

Towards the tail

Rostral

Within the head towards the nose or muzzle

Ventral

Toward the belly

Dorsal

Toward the back

Proximal

Nearer or closer to the body (refers to a limb or extremity)

Distal

Farther or away from the body (refers to a limb or extremity)

Lateral

Farther from the midline or median plane or towards the side of the body

Medial

Closer to the midline or median plane or towards the middle

Palmar

Ground surface of front foot

Plantar

Ground surface of hind foot

Superficial

Toward the outer surface of the body

Deep

Toward the inner core of the body

Carpus

Join and region on the front leg that corresponds to the human wrist.

Tarsus

Tarsus in a dog refers to the hock, which is the joint equivalent to the human ankle on the hind leg.

Right Lateral View

patient lies or stands with their right side closest to the image detector

Left Lateral View

where the patient stands or lies with their left side touching the image receptor

Ventro-dorsal VD view

beam enters the front (ventral/belly) side of the body and exits through the back (dorsal/spine) side, with the patient lying on their back

Dorso-ventral DV view

beam enters from the animal's back (dorsal side) and exits through the belly (ventral side), with the patient lying on their stomach in sternal recumbency

Common Regional Terms: Horse

Refer to Image

Dorsal Body Cavity

Central Nervous System: Cranial Cavity and Spinal Cavity

Ventral Body Cavity

CRANIAL Thoracic (chest): Enclosed by the rib cage. Contains major structures e.g. Heart, lungs, blood vessels, esophagus

CAUDAL Abdominal: Largest cavity. Contains digestive, and urinary, organs

Cranial Cavity

Formed by skull bones; houses and protects the brain.

Spinal Cavity

Formed by spinal vertebrae; houses and protects the spinal cord.

Pelvic cavity

The caudal portion of the ventral cavity enclosed by pelvic bones, housing the retum and internal reproducive organs.

Pleura

Lines thoracic cavity

Structure:

Visceral Layer: The inner layer that tightly covers the surface of the lungs.

Parietal pleura: The outer layer that attaches to your chest wall and diaphragm.

Pleural space: A tiny, fluid-filled gap separating the two layers. This fluid acts as a lubricant so the tissues glide smoothly when you breathe.

Peritoneum

Lines abdominal cavity

Visceral layer: The inner layer that wraps around and covers the abdominal organs (viscera).

Parietal layer: The outer layer that lines the inner walls of the abdominal and pelvic cavities, as well as the underside of the diaphragm.

Potential Space: The potential space between the two layers, containing a small amount of lubricating fluid that lets organs move without friction

Inflammation of the pleura

pleuritis / pleurisy

Inflammation of the peritoneum

peritonitis

Diaphragm

A dome-shaped skeletal muscle partition separating thoracic and adominal cavites, crucial for respiratiom.

Organization of the body

Cells, Tissues, Organs, Systems

Cells

Basic units of life, have specialized functions

Tissues

Groups of specialized cells, e.g. Epithelial, Connective, Muscle, Nervous

Organs

Groups of tissues working together e.g. Brain, Heart, Eyes, Lungs

Systems

Group of organs, involved in set of activities e,g, Digestive system

Major organ systems

Nervous, Cardiovascular, Respiratory, Urinary system

Homeostasis

Physiological processes maintain the bodys equilibrium (balance) in the various structures, functions, and properties.

Makes life possible.

Disease

The result when structures or functions of the body become abnormal

Ligament

strong band of dense connective tissue spanning between bones across joint, Connects bone to bone

Tendons

Connects muscle to bone

Epithelial Tissue

Cells that cover and line other tissues

Protect underlying tissue and filter biochemical substances

Absorb, secrete, or excrete biochemical substances

Play a role in reception of sensory input

Characteristics of Epithelia

Apical surface: Faces the lumen or outside of organ

Basal surface: Faces the basal lamina and blood vessels

Lateral surface connected to cells by junctional complexes

Are avascular (without blood supply)

Are innervated (have nerve endings)

Secrete

Purpose: Produce and release substances that body needs to perform functions e.g digestion, lubrication, or regulation

Products: Hormones, enzymes, mucus, saliva, sweat, oil

e.g- Salivary glands secrete saliva to help digest food.

– Sweat glands secrete sweat to help cool the

Excretion

Purpose: To eliminate metabolic waste products and other unwanted substances from the body

Products Urine (w urea), Feces, exhaled carbon dioxide

e.g.-The lungs excrete carbon dioxide when we breathe out.

– The digestive system eliminates undigested solid waste, also called elimination or defecation

Cellular Attachments

1. Tight junctions

2. Desmosomes

3. Gap junctions

Tight junctions

Formed by fusion of the outermost layers of plasma membranes of cells

Found in leak proof tissues: e.g. Urinary bladder, Digestive tract

Desmosomes

Mechanical coupling made by Filaments that interlock with one another

Found in tissue that undergo repeat tension and stretching e.g skin, heart, uterus

Gap junctions

Tubular channel proteins (connexons) extend from cytoplasm of one cell to the cyto.. of another

Allow the exchange and passage of ions and nutrients

Found in intestinal epithelial cells, heart, smooth muscle tissue

Basement Membrane

also called Basal lamina a meshwork of fibers that cement epithelial cells to the underlying connective tissue and partial barrier between them

Vary in thickness

Helps prevent the cell from being torn off by the intraluminal pressures

Surface Specialization

Surface of epithelial cells vary depending on where they are located and their role: Smooth, Microvilli (brush border), Cilia, Keratin

Classification of Epithelial Tissue

1. Number of layers of cells: Simple, Stratified

2. Shape of cells: Squamous, Cuboidal, Columnar

3. Surface specializations: Cilia, Keratin, etc

Simple Squamous Epithelium

Found lining surfaces involved in the passage of gas or liquid, e.g Lungs

Fraglie, thin, flat, and smooth

Simple cuboidal epithelium

In areas of body where secretion and absorption take place e,g Kidney

Single layer, cube shaped, round, dark nuclei aligned in a row

Simple Columnar Epithelium

Found in excretory ducts as well as digestive tract

Elongated and closely packed, Nucleui aligned in a row at base near basement membrane

Stratified Squamous Epithelium

Multilayered

Occur in areas where body is subjected to mechanical and chemical stresses e.g oral cavity, skin

Protect underlying tissue

Stratified Cuboidal Epithelium

Two layers

Found along large excretory ducts e.g salivary glands, sweat glands

Protects underlying tissue

Stratified Columnar Epihelium

Found in select parts of respiratory, digestive, reproductive

Function in secretion and protection

Pseudostratified Columnar Epithelium

Cell nuclei found at different levels

Some cells do not reach the luminal surface

Found in respiratory tract and portions of the male reproductive tract

Pseudostratified Columnar Epithelium

Cell nuclei found at different levels

Some cells do not reach the luminal surface

Found in respiratory tract and portions of the male reproductive tract

Transitional Epithelium

Basal layer of cuboidal or columnar cells and superficial layer of cuboidal or squamous cells

Found in areas of body required to expand and contract as normal function e,g urinary bladder

Endocrine Glands

Do not have ducts or tubules, secretions are distributed throughout the body

Produce and secrete hormones into the bloodstream or lymphatic system

Complex biochemical network known as endocrine system

Exocrine Glands

Discharge secretions via ducts directly into local areas except for goblet cells

Unicellular or multicellular

Connective Tissue

Tissue where cells are suspended outside of the cell

Functions:

Form metabolic and structural connections between other tissues

Form protective sheath around organs and insulates the body

Reserve for energy

Frame that supports body

Composes medium that transports substances

Plays a role in the healing process and controls invading microorganisms

Connective tissue components

Extracellular Matrix

• Extracellular fibers

• Ground substances

Cells

Ground substance

Where cells exchange nutrients and waste with the bloodstream

Ranges in texture from liquid or gel to a calcified solid

Extracellular fibers

Strong thick strands of collagen, found in tendons and ligaments

Reticular fibers

Thin delicate networks of collagen

Provide support for high cellular organs, e,g endocrine glands, lymph modes, spleen, liver, blood vessels, nerves

Elastic fibers

Composed primarily of the protein elastin, coiled microfibrils, occurs in tissues commonly subjected to stretching e.g vocal cords, lungs, skin

Cell Types

Fixed cells: involved in production and maintenance of matrix e.g. fibroblasts, chondroblasts, osteoblasts

Transient cells: involved in the repair and protection of tissues e.g leukocytes, mast cells

Connective tissue proper

Loose connective tissue: Areolar, Adipose, Reticular

Dense connective tissue: Dense regular, Dense irregular, Elastic

Areolar Connective Tissue

Loose, Predominant cell is the fibroblast

Manufactures the elastic, reticular, and collagenous fibers

Surrounds every organ; present in all mucous membranes

Adipose Tissue

Loose, Areolar tissue in which adipocytes predominate cell, highly vascular, Energy storehouse and thermal insulator FAT CELLS

Reticular Connective Tissue

Loose, network of thin reticular fibers, loosely arranged fibers and fibroblasts suspended, forms the stroma (framework of several organs) e.g spleen

Dense Regular Connective Tissue

Tightly packed parallel collagen fibers

Avascular (no blood supply)

Makes up the tendons ( muscles to bones) Ligaments (bone to bone)

Dense Irregular Connective Tissue

Found in the dermis of the skin, Composed primarily of collagen fibers, interwoven to form single sheet,

Elastic Connective Tissue

Elastic fibers, parallel or interwoven and collagenous fibers interspersed, Found in spaces between vertebrae and in areas of body that require stretching, e.g wall of arteries, stomach , bladder

Specialized Connective Tissue

Cartilage

• Hyaline cartilage

• Elastic cartilage

• Fibrocartilage

Bone

Blood

Cartilage

Found in joints in ear, nose, vocal cords

Forms a framework on which bone is formed

No innervation: avascular

Hyaline Cartilage

Most common type of cartilage found in body, made of closely packed collagen

Found in joints at the end of long bones, tracheal rings, and connections of the ribs to the sternum, coastal cartilages

Elastic cartilage

Contains elastic fibers in dense branching bundles

Flexible: can withstand bending

Found in epiglottis of larynx and pinnae of ears

Nervous Tissue

Transmits electrical impulses throughout the body. (e.g., neurons, spinal cord).

Fibrocartilage

Merged with hyaline cartilage and dense connective tissue, found in space between vertebrae of the spine, between bones in pelvic girdle, knee joint

Bone

Combo of organic collagen fibers and inorganic calcium salts, Well vascularized (blood vessels), Haversian canal contain both vascular and nerve supply

Osteoblasts

Manufacture the fibers that are part of the matrix. specialized cells responsible for creating and forming new bone tissue.

Osteocytes

Reside in lacunae (unfilled spaces/gaps)

Blood

Matrix:

- Ground Substance: plasma

- Fibrous component: protein

Cells:

• Erythrocytes

• Leukocytes

• Thrombocytes

Mucous Membranes (mucosae)

Line organs w connections to the outside environment (mouth, nasal passage, intestine)

Composed of stratifies squamours or simple columnar epithelium covering layer of connective tissue

Submucosa: connective tissue layer that connects muscosa to underlying structures

May contain goblet cells or multicellular glands

• can produce large quantities of mucus

• mucus consists primarily of water, electrolytes, and the protein mucin

Some can absorb e.g. epithelial in the intestine

Serous Membranes (serosae)

Lines the walls and cover organs e.g thorax and abdominopelvic cavities)

Consists of continuous sheet doubled over to form two layers

The portion of the membrane that lines the cavity wall is called the parietal layer

The portion of the membrane that covers the outer surface of organs is called the visceral layer

In abdominopelvic cavity, visceral layers of serosa merge to form mesenteries ( attaches the intestine to wall around stomach and holds it in place)