Lab 18: Histology

histology

the microscopic study of animal cells and tissues; structure leads to function

cell

the basic structural and functional unit of all life

tissue

a collection of cells that have similar structures and functions

organ

a collection of different tissues working together for a specific function

Epithelial tissue

Tissue that covers internal and external body surfaces and functions in protection, absorption, and secretion.

ex. simple squamous, stratified squamous, simple cuboidal, simple columnar

found in digestive, respiratory, reproductive, circulatory, and integumentary systems

Apical surface

The exposed surface of epithelial tissue facing the body cavity, lumen, or external environment.

Basal surface

The bottom surface of epithelial cells that attaches to the basement membrane.

Basement membrane

A thin layer that anchors epithelial tissue to the underlying connective tissue.

Simple epithelium

A single layer of epithelial cells attached to the basement membrane.

Stratified epithelium

Multiple layers of epithelial cells stacked on top of each other; tissue named by shape of cell on apical surface

Squamous cells

Thin, flat epithelial cells specialized for diffusion and filtration.

Cuboidal cells

Cube-shaped epithelial cells specialized for secretion and absorption.

Columnar cells

Tall, column-shaped epithelial cells specialized for absorption and secretion.

frog kidney tubules

simple cuboidal epithelium rolled into a tube

simple cuboidal epithelium

specialized for secretion and absorption

frog intestinal lining

simple columnar epithelial cells; structured to maximize surface area for nutrient absorption

intestinal villi

finger-like projections of epithelial tissue into the intestinal lumen

microvilli

microscopic membrane protrusions from individual epithelial cells

Connective tissue

Tissue that supports, binds, protects, and connects other tissues in the body; internal transport, storage, and insulation

ex. adipose, blood, bone, dense fibrous, loose fibrous, hyaline cartilage

found in integumentary, circulatory, skeletal, musculoskeletal systems

Extracellular matrix

Nonliving material surrounding connective tissue cells that provides support and structure; network of proteins and minerals that may be liquid, semi-solid, or solid

Loose connective tissue

A connective tissue with loosely arranged thin mesh fibers that holds organs and tissues together.

Dense connective tissue

Connective tissue with densely packed collagen fibers that provides strong structural support; high tensile strength (resistant to stretching); includes ligaments and tendons

Ligaments

Dense connective tissue that connects bone to bone.

Tendons

Dense connective tissue that connects muscle to bone.

Cartilage

Flexible connective tissue that provides support and cushioning in structures like the nose, ears, and joints.

chondroitin sulfate

protein-carbohydrate complex that gives the cartilage a jelly-like consistency

Chondrocytes

Cells that produce and maintain cartilage.

Lacunae

Small spaces within the extracellular matrix that house cells such as chondrocytes and osteocytes.

bone

hard, mineralized connective tissue that comjprises the skeleton of vertebrate animals

Compact bone

Dense bone tissue that forms the hard outer layer of bones.

bone matrix

contains calcium, magnesium, and phosphate to make it solid

Osteocytes

bone cells

Haversian canal

central canal tubes in the osteon matrix for nerves and blood vessels to run through

Lamellae

Concentric layers of bone matrix surrounding the Haversian canal, arranged in concentric circles.

Canaliculi

Tiny thin channels in the matrix connecting lacunae and Haversian canal that allow nutrient and waste exchange between bone cells.

Osteon

The structural unit of compact bone consisting of a Haversian canal surrounded by lamellae.

Blood

A liquid connective tissue that transports oxygen, nutrients, wastes, and immune cells throughout the body; composed of blood plasma, erythrocytes, leukocytes, and platelets

Plasma

fluid matrix; the liquid component of blood that carries cells, nutrients, hormones, and waste products.

Erythrocytes

Red blood cells that carry oxygen using hemoglobin.

Leukocytes

White blood cells involved in immune defense.

Platelets

Cell fragments that help with blood clotting.

Adipose

Connective tissue specialized for fat storage, insulation, and cushioning.

Nervous tissue

Tissue specialized for communication through electrical and chemical signals; transmitting and receiving signals to control the body; collect sensory info, coordinate action, perform mental activity

composed of two classes of cells: neurons and glia

found in central and peripheral nervous systems

Neuron

A nerve cell that sends and receives electrochemical signals in the nervous system; consists of cell body/soma, axon, and dendrites

Cell body/soma

The part of a neuron containing the nucleus.

Axon

a long projection of a neuron that sends signals

Dendrites

Branched extensions of a neuron that receive signals.

Neural processes

Extensions of neurons including axons and dendrites.

Glial cells

provide structural and nutritional support to neurons

Muscle tissue

Tissue specialized for contraction in response to nerve signals to produce movement.

ex. skeletal, cardiac, smooth

found in musculoskeletal, cardiovascular, and digestive systems

Skeletal muscle

Striated voluntary muscle attached to bones that moves the skeleton.

Cardiac muscle

Striated involuntary muscle responsible for contraction of the heart.

Intercalated disc

Specialized junctions between cardiac muscle cells that allow rapid electrical communication.

Smooth muscle

Non-striated involuntary muscle found in internal organs and blood vessels.

Striations

Visible banding patterns in skeletal and cardiac muscle caused by organized contractile proteins.

Voluntary muscle

Muscle under conscious control, such as skeletal muscle.

Involuntary muscle

Muscle that contracts automatically without conscious control, such as cardiac and smooth muscle.

Skin

The largest organ of the body that protects against environmental damage and regulates temperature.

Epidermis

The outermost layer of skin made of stratified squamous epithelial tissue.

Dermis

The middle layer of skin containing connective tissue, glands, blood vessels, and nerves.

Hypodermis

The deepest layer of skin composed mainly of adipose tissue for insulation and energy storage.

Keratinized layer

A tough, protective outer layer of dead cells in the epidermis filled with keratin.

Sebaceous glands

Oil-producing glands in the skin that secrete sebum to lubricate hair and skin.

Sweat glands

Glands that produce sweat to regulate body temperature.

Chromatophores

Pigment-containing cells that give color to frog skin.

Mucus glands

Glands in frog skin that secrete mucus to keep the skin moist.

Poison gland

Specialized gland in frog skin that secretes toxins for defense.