Comprehensive Anatomy and Tissue Types: Epithelial, Connective, Muscle, Nervous

Epithelial

Connective

Provides support

Cartilage, tendons, ligaments

Muscle

tissue composed of fibers that can contract, causing movement of an organ or part of the body

Nervous

Brain of the tissues: controls everything

Functions of Epithelial Tissue

Protection, Absorption, Secretion, Excretion, Sensory reception

Cellular Junctions

Tight junctions, Desmosomes, Gap junctions

Basement Membrane

Structure: basal lamina + reticular lamina; Function: support, anchor, barrier

Classification of Epithelial Tissue

By number of layers: simple vs stratified; By cell shape: squamous, cuboidal, columnar; Special types: pseudostratified, transitional

Classification of Glands

By presence of ducts: endocrine vs exocrine; By secretion type: serous, mucous, mixed; By mode of secretion: merocrine, apocrine, holocrine

Components of Connective Tissue

Cells (fibroblasts, adipocytes, macrophages, mast cells, etc.); Fibers (collagen, elastic, reticular); Ground substance

Types of Loose CT

Areolar, Adipose, Reticular

Types of Dense CT

Dense regular, Dense irregular, Elastic

Cartilage

Hyaline, Elastic, Fibrocartilage

Bone Components

Cells (osteoblasts, osteocytes, osteoclasts); Matrix (organic + inorganic)

Skeletal Muscle

Straited muscle

Voluntary muscle

Cardiac Muscle

Found only in the heart

Small, branching cells with only one nucleus

Connected via intercalated disks

Contains specialized pacemaker cells to signal contractions at regular intervals

Striated

Involuntary

Smooth Muscle

Small, spindle-shaped cells

Nonstriated

Contractions cannot be consciously controlled

Involuntary

Found in walls of hollow organs

Blood vessels, urinary bladder, uterus, intestines, stromach,

Responsible for peristalsis

Neuron Components

Cell body (soma), Dendrites, Axon

Supporting cells (neuroglia)

Healing

Inflammation, Organization (granulation tissue), Regeneration

Epidermis

Cell types: keratinocytes, melanocytes, Merkel cells, Langerhans cells; Five layers (stratum basale, spinosum, granulosum, lucidum, corneum); Keratinization process

Dermis

Structures: connective tissue, blood vessels, nerves, glands, hair follicles; Functions: support, thermoregulation, sensation

Hypodermis

Loose connective tissue, adipose tissue; Provides insulation, cushioning, energy storage

Special Features of Integumentary System

Paw pads, Planum nasale

Hair

Follicle structure; Growth process; Three types: primary/guard, secondary/wool, tactile/vibrissae

Glands

Sebaceous glands: structure & location; Sweat glands: eccrine vs apocrine

Tissues

Cells of similar type and function clustered together.

Blood-brain barrier

Helps protect the brain by filtering substances.

Secretions

Substances made to stay inside the body, such as hormones and enzymes.

Excretions

Substances secreted outside of the body, like sweat, milk, and poop.

Connective tissue

Provides support; includes cartilage, tendons, and ligaments.

Nervous tissue

Controls everything; often referred to as the brain of the tissues.

Characteristics of epithelia

Organized tightly packed groups that form sheets; each cell is polar with apical and basal surfaces.

Apical surface

The top surface of a polar cell that faces the body.

Basal surface

The bottom surface of a polar cell that faces the body.

Lateral surfaces

Connect neighboring cells in epithelial tissue.

Avascular

Epithelial cells rely on diffusion for nutrients.

Innervated

Most epithelial cells have nerves.

Cellular attachments

Plasma membranes join to form specialized attachments.

Junctional complexes

Specialized attachments formed by plasma membranes of adjoining cells.

Tight junctions

Formed by fusion of outermost layers of plasma membranes of adjoining cells, preventing leaks.

Desmosomes

Connect the plasma membranes of adjacent cells, providing strong mechanical coupling.

Gap junction

Cells linked by tubular channel proteins allowing exchange of ions and nutrients.

Surface specialization

Surfaces vary depending on their location and role in tissue function.

Microvilli

Brush borders found in the intestines that absorb nutrients.

Cilia

Found in the upper respiratory tract, coated with mucous to trap waste.

Keratin

Waxy substance found in skin cells that makes them waterproof.

Classification of epithelia

Based on number of layers, shape of cells, and presence of surface specialization.

Simple epithelium

One layer of cells, found in glands and blood vessels.

Stratified layers

Multiple layers of cells, such as in skin.

Transitional epithelium

Found in the urinary tract and stretches.

Goblet cell

A ductless gland made up of one cell that secretes mucin.

Mucoid secretion

Thick, jelly-like secretion.

Serous secretion

Watery secretion, like tears, sweat, and enzymes.

Endocrine gland

Expresses to the inside and has a duct.

Exocrine gland

Expresses to the outside.

General Characteristics of Connective Tissue

Most abundant tissue by weight, vascularized, with three distinct components: ground substance, extracellular fibers, and cells.

Loose connective tissue

Areolar tissue, a tangle of random fibers and cells suspended in thick ground substance.

Adipose tissue

Fat tissue where adipocytes predominate, located throughout the body.

White adipose

Contains 7x more sugar than brown adipose.

Brown adipose

Found in young immature animals and animals that hibernate.

Energy storage

It has 10x more energy than white adipose.

Thermal insulator

A function of connective tissue that helps to retain body heat.

Mechanical shock absorber

A function of connective tissue that protects organs from impact.

Reticular tissue

Thin, loosely arranged reticular fibers and fibroblasts suspended in ground substance.

Stroma

The framework for organs formed by reticular tissue.

Dense connective tissue

Not very vascular, takes a long time to heal, similar to tendons and ligaments.

Dense Regular

Tightly packed parallel collagen fibers with fibroblasts forming rows.

Tendons

Locations where dense regular connective tissue is found.

Ligaments

Locations where dense regular connective tissue is found.

Sheets of fascia

Locations where dense regular connective tissue is found.

Dense Irregular

Designed to be mobile with thicker bundles of collagen interwoven into a single sheet.

Dermis of skin

Location where dense irregular connective tissue is found.

Fibrous covering of organs

Location where dense irregular connective tissue is found.

Tough capsule of joints

Location where dense irregular connective tissue is found.

Elastic connective tissue

Composed primarily of elastic fibers in a parallel or interwoven pattern with fibroblasts and collagen.

Spaces between vertebrae

Location where elastic connective tissue is found.

Body regions that require stretching

Locations such as ligaments and walls of arteries, stomach, bronchi, bladder, and heart.

Specialized connective tissue

Includes cartilage, osseous connective tissue (bone), and blood.

Hyaline cartilage

Found at the ventral part of the ribs where they reach the sternum and in the skeleton of a growing fetus.

Chondrioblasts

Cells that form hyaline cartilage and multiply to heal if injured.

Elastic fibrocartilage

Found in ears mostly.

Osseous connective tissue

Also known as bone.

Blood

Connective tissue that connects the whole body, with ground substance as plasma.

Platelets

Cells in blood that are involved in clotting.

Fibrocartilage

Contains collagenous fibers and cartilage cells in lacuna.

Membranes

Thin protective layers of tissue linked together.

Mucous membranes

Line organs with connections to outside environments and function to cover and protect in the GI tract.

Serous membranes

Line walls and cover organs that fill closed body cavities.

Parietal layer

The layer of serous membranes that lines the body wall.

Visceral layer

The layer of serous membranes that touches the organ itself.

Mesenteries

Layers that merge to form in the abdominopelvic cavity.

Omentum

Broad ligament.

Synovial membranes

Lines the cavities of joints.

Connective and adipose tissue

Covered by a layer of collagen fibers and fibroblasts.

Synovial fluid

Manufactured to fill joint spaces.

Serosal fluid

Small amounts normally found in body cavities.

Effusion

Abnormally low amounts of serosa produced.

Ascites

A type of effusion.

Nephrosis

A type of effusion.