BIO65 || CH3: Histology - The Study of Tissues

Epithelial Tissue

Tissue that can be found in one or more layers, with closely adhered cells covering surfaces, avascular, anchored to a basement membrane, and having basal and apical surfaces.

Simple Epithelium

Epithelium consisting of a single layer of cells.

Pseudostratified Columnar Epithelium

Columnar epithelium where it is unclear whether there is one layer or multiple layers of cells.

Stratified Epithelium

Epithelium consisting of two or more layers of cells.

Squamous Cells

Flat cells shaped like a triangle or hexagon.

Cuboidal Cells

Cells with a square or hexagonal shape, resembling a cube.

Columnar Cells

Cells shaped like cylinders.

Simple Squamous Epithelium

Single layer of thin cells found in areas like lung air sacs and kidneys, allowing rapid diffusion of materials.

Simple Cuboidal Epithelium

Single layer of 'box' cells mainly found in the liver, thyroid, and kidney tubules for absorption and secretion.

Simple Columnar Epithelium

Tall, columnar cells found in intestines, gallbladder, and uterus for absorption.

Pseudostratified Columnar Epithelium

Epithelium where some cells touch the basement membrane while others do not, secreting and propelling mucus.

Keratinized Stratified Squamous Epithelium

Epithelium with flat cells in layers of dead cells, found in the epidermis, palms, and soles for abrasion resistance.

Non-keratinized Stratified Squamous Epithelium

Epithelium without multiple layers of dead cells, found in areas like the tongue, esophagus, and vagina for abrasion resistance.

Urothelium (Transitional) Epithelium

Epithelium that can change shapes and expand, found in the urinary tract for stretching and flattening.

Connective Tissue

Tissue that binds organs, provides support, physical and immune protection, allows movement, storage, heat production, and transport.

Areolar Connective Tissue

Loose connective tissue abundant in the body, binding epithelium to deeper tissue.

Dense Regular Connective Tissue

Highly organized tissue with mostly collagen fibers, found in tendons and ligaments for strength.

Dense Irregular Connective Tissue

Tissue with a random arrangement of collagen fibers, providing stress resistance, found in the dermis.

Adipose Tissue

Tissue that stores energy and provides protection, making up a significant portion of the human body.

Hyaline Cartilage

Cartilage with a glassy texture, found in windpipes, trachea, and bronchi for toughness.

Elastic Cartilage

Cartilage with elastic fibers, found in the external ear for flexibility and elastic support.

Fibrocartilage

Tough cartilage with parallel collagen fibers, located in intervertebral discs for shock absorption.

Spongy (Trabecular) Bone

Bone tissue arranged in thin rods and plates with pores, providing stress resistance in multiple directions.

Compact (Cortical) Bone

Bone tissue arranged in osteons with central canals, lamellae, lacunae with osteocytes, and canaliculi for nutrient transport.

Plasma

Liquid part of blood containing water, salts, enzymes, leukocytes, and platelets.

Neurons

Cells that transmit information in the nervous system, consisting of neurosoma, dendrites, and axons.

Skeletal Muscle

Voluntary muscle attached to bones, with long parallel fibers, multinucleated cells, and striations.

Cardiac Muscle

Involuntary muscle forming most of the heart walls, with branched fibers, striations, and intercalated discs.

Smooth Muscle

Involuntary muscle with spindle-shaped myocytes found in hollow organs, lacking striations.

Endocrine Glands

Glands that secrete hormones directly into the bloodstream WITHOUT DUCTS.

Exocrine Glands

Glands that USE DUCTS to secrete substances onto body surfaces or into body cavities.

Reticular Connective Tissue

forms supporting tissue in walls of liver, lymph nodes and spleen

Cells & Structures of Cartilage Connective Tissue

Chondroblasts/Chondrocytes, Lacuna, Fibroblasts, Extracellular matrix

Chondroblasts/Chondrocytes (cartilage tissue)

Produce and maintain extracellular matrix in cartilage tissue

Lacuna (cartilage)

House the mature chondrocytes

Fibroblasts (cartilage)

produce fibers and ground substance

Extracellular Mix (cartilage)

Structure surrounding cells. Has a low oxygen environment and lack of vasculature

Neuroglia (glial) cells

cells that support and protect neurons

Neurosama

cell body of a neuron

Dendrites

Branchlike parts of a neuron that are specialized to receive information.

Axon

A threadlike extension of a neuron that carries nerve impulses away from the cell body.

Types of Exocrine Glands

eccrine (merocrine), apocrine, holocrine

Serous glands

watery secretions

Mucous Glands

Secrete mucin that absorbs water to form mucus

Eccrine (merocrine) glands

glands that produce sweat; found over most of the body
Exocytosis
→ Found in Tear glands, pancreas, gastric glands, others

Apocrine glands

glands that lose small portions of their glandular cell bodies during secretion
→ Droplets bud from surface
→ Functional at puberty - mammary & axillary glands

Holocrine glands

→ Entire cell pinches off
→ Oil-producing glands of scalp & eyelid

Hyperplasia

increase in number of cells

Hypertrophy

increase in cell size

Neoplazia

tumor development

Differenation

Specialization of form or function

Metaplasia

Mature cell type is replaced by a different mature cell type

Regeneration

Replacement of dead cells

Fibrosis

Scar tissue development

Atrophy

reduction in size

Necrosis

pathological death of tissue

Infarction

death of tissue due to cutting off blood supply

Gangrene

another form of necrosis due to insufficient blood supply

Apoptosis

programmed cell death

Four types of Tissues

epithelial, connective, muscle, nervous

TYPES OF TISSUES: FOUR C'S

Epithelial - Covers
Connective - Connects
Nervous - Conducts
Muscular - Contracts