Comprehensive Tissue Types and Membrane Functions in Human Anatomy

What are the three main types of cells based on shape in epithelial tissue?

Squamous, cuboidal, and columnar.

What is the primary function of epithelial tissue?

To cover and protect surfaces, both outside and inside the body.

What characterizes simple squamous epithelium?

It consists of a single layer of thin, flat cells.

What is the difference between simple and stratified epithelium?

Simple epithelium has one layer of cells, while stratified epithelium has multiple layers.

What is pseudostratified columnar epithelium?

A type of epithelium that appears falsely stratified but consists of a single layer of cells attached to the basement membrane.

What are the functions of epithelial tissue?

Protects underlying structures, acts as a barrier, permits passage of substances, secretes substances, and absorbs substances.

What is the structure of simple cuboidal epithelium?

A single layer of cube-shaped cells that carry out active transport, facilitated diffusion, or secretion.

What is the function of keratinized stratified squamous epithelium?

It functions in protection and is found in the outer layer of the skin.

What is the role of nonkeratinized stratified squamous epithelium?

It provides protection and is found in moist areas like the mouth and esophagus.

What is the significance of the basement membrane in epithelial tissue?

It anchors the epithelial tissue to underlying structures and provides support.

What is the primary characteristic of columnar cells?

They tend to be taller than they are wide.

What is histology?

The study of tissues.

What is the function of simple columnar epithelium in the small intestine?

It produces and secretes mucus and digestive enzymes.

What distinguishes stratified cuboidal epithelium?

It consists of more than one layer of cuboidal epithelial cells.

What is the function of epithelial tissues in glands?

They are involved in secretion, including exocrine and endocrine glands.

What is the role of simple squamous epithelium in the lungs?

It allows for gas exchange.

What is the role of simple squamous epithelium in the kidneys?

It helps filter wastes from the blood while keeping blood cells inside the blood vessels.

What is the characteristic of stratified squamous epithelium?

It forms a thick epithelium due to several layers of cells.

What is the appearance of pseudostratified columnar epithelium?

It appears stratified due to variations in cell shape, but is actually a single layer.

What type of epithelial tissue is found in sweat gland ducts?

Stratified cuboidal epithelium.

What is the function of epithelial tissue in absorption?

It allows for the uptake of substances, such as nutrients in the intestines.

What is the significance of the shape of surface cells in stratified epithelium?

The naming is based on the shape of the surface cells, regardless of the shape of deeper cells.

What is stratified columnar epithelium and where is it found?

Stratified columnar epithelium consists of multiple layers of epithelial cells with surface cells that are columnar and deeper cells that are irregular or cuboidal. It is found in the mammary gland ducts, the larynx, and a portion of the male urethra.

What are the main functions of stratified columnar epithelium?

Stratified columnar epithelium carries out secretion, protection, and some absorption.

How do cilia in the airways function?

Cilia in the airways move mucus and accumulated debris toward the throat for swallowing.

What is the characteristic of nonkeratinized stratified squamous epithelium of the mouth?

It is a moist epithelium that provides protection against abrasion and acts as a mechanical barrier.

How does the permeability of nonkeratinized stratified squamous epithelium compare to keratinized stratified squamous epithelium?

Water can move across nonkeratinized stratified squamous epithelium more readily than across keratinized stratified squamous epithelium.

What is transitional epithelium and where is it found?

Transitional epithelium is a special type of stratified epithelium that can be greatly stretched, found lining cavities that can expand greatly, such as the urinary bladder.

What is the role of tight junctions in epithelial tissue?

Tight junctions prevent the passage of materials between epithelial cells and regulate what materials can cross the epithelial layer.

Where are tight junctions commonly found?

Tight junctions are found in the lining of the intestines.

What are endocrine glands and how do they function?

Endocrine glands are ductless glands that secrete their products (hormones) directly into the bloodstream.

What distinguishes exocrine glands from endocrine glands?

Most exocrine glands are multicellular and have ducts through which they secrete their products.

What are the characteristics of simple exocrine glands?

Simple exocrine glands have a single, non-branched duct; some may have branched ducts.

What are compound exocrine glands?

Compound exocrine glands have multiple, branched ducts.

What is the function of microvilli in epithelial cells?

Microvilli increase the surface area of epithelial cells.

What are goblet cells and their function?

Goblet cells are single-cell exocrine glands that secrete mucus.

What are the types of secretory regions in glands?

Secretory regions can be tubular (small tubes) or saclike (acinar or alveolar).

What are tubuloacinar or tubuloalveolar glands?

Glands that have a combination of tubular and saclike secretory regions.

What are desmosomes and their function?

Desmosomes are mechanical links that bind cells together.

What is the role of gap junctions in epithelial cells?

Gap junctions are small channels that allow small molecules and ions to pass between adjacent epithelial cells, facilitating communication.

What are the three main functions of intercellular junctions in epithelial tissue?

They mechanically bind cells together, help form a permeability barrier, and provide a mechanism for intercellular communication.

What is the significance of the free surface in epithelial tissue?

Most epithelia have a free surface that is not in contact with other cells and faces away from underlying tissues, which can be smooth or lined with microvilli or cilia.

What are hemidesmosomes?

Half desmosomes that anchor cells to the basement membrane.

What are the three major components of the extracellular matrix in connective tissue?

Protein fibers, ground substance, and fluid.

What does ground substance consist of?

Non-fibrous protein and other molecules.

How can exocrine glands be classified based on product release?

Merocrine, apocrine, and holocrine.

What characterizes merocrine secretion?

The release of secretory products by exocytosis.

What characterizes apocrine secretion?

The release of secretory products as pinched-off fragments of the gland cells.

What characterizes holocrine secretion?

The shedding of entire cells.

What are the functions of connective tissue?

Enclosing and separating tissues, connecting tissues, supporting and moving parts, storing compounds, cushioning and insulating, transporting, and protecting.

What are the three types of protein fibers found in connective tissues?

Collagen, reticular, and elastic fibers.

What are the characteristics of collagen fibers?

They resemble microscopic ropes, are very flexible, and resist stretching.

What are reticular fibers?

Very fine, short collagen fibers that branch to form a supporting network.

What is the function of elastic fibers?

They can return to their original shape after being stretched or compressed.

How does connective tissue differ from other tissue types?

It consists of cells separated by an abundant extracellular matrix.

What are osteoblasts, osteocytes, and osteoclasts?

Osteoblasts form bone, osteocytes maintain it, and osteoclasts break it down.

What role do fibroblasts and fibrocytes play in connective tissue?

Fibroblasts form fibrous connective tissue, and fibrocytes maintain it.

What do chondroblasts and chondrocytes do?

Chondroblasts form cartilage, and chondrocytes maintain it.

What are macrophages?

Large cells capable of moving about and ingesting foreign substances in connective tissue.

What are mast cells?

Nonmotile cells that release chemicals, such as histamine, promoting inflammation.

What are proteoglycans?

Large molecules consisting of a protein core attached to many long polysaccharides.

What is the significance of dense elastic connective tissue?

It has abundant elastic fibers that allow the tissue to stretch and recoil, as seen in the vocal cords.

What is Marfan syndrome?

A condition resulting from the inability to properly maintain and form elastic fibers.

What are the two main types of connective tissue?

Embryonic and adult connective tissue.

What happens to embryonic connective tissue by eight weeks of development?

Most of it becomes specialized to form the types of connective tissue seen in adults.

What are the three subdivisions of loose connective tissue?

Areolar, adipose, and reticular.

What is the primary composition of areolar connective tissue?

Collagen fibers and a few elastic fibers.

What type of cells are most common in loose connective tissue?

Fibroblasts.

What is the primary function of adipose tissue?

Energy storage, padding, protection, and thermal insulation.

What are the two major subcategories of dense connective tissue?

Collagenous and elastic.

What characterizes dense regular connective tissue?

Collagen fibers oriented in the same direction.

What is an example of dense regular connective tissue?

Tendons and ligaments.

What is the role of reticular tissue?

It forms the framework of lymphatic tissue, such as in the spleen and lymph nodes.

What are the main components of cartilage?

Chondrocytes located in lacunae within an extensive matrix.

What gives cartilage its flexibility and strength?

Collagen in the matrix.

What is the function of elastic cartilage?

It can recoil to its original shape when bent.

Where is elastic cartilage found?

In the external ear, epiglottis, and auditory tube.

What is the most abundant type of cartilage?

Hyaline cartilage.

What is blood classified as?

A liquid connective tissue.

What is the liquid matrix in blood called?

Plasma.

What are the formed elements in blood?

Erythrocytes, leukocytes, and platelets.

What are the two types of bone tissue?

Spongy bone and compact bone.

What characterizes spongy bone?

It has spaces between trabeculae and resembles a sponge.

What is the main function of muscle tissue?

To contract, enabling movement.

What are the three types of muscle tissue?

Skeletal, cardiac, and smooth.

What is the function of skeletal muscle?

It attaches to the skeleton and enables body movement.

What is fibrocartilage known for?

Its strength and rigidity, providing support.

What type of muscle cells are striated and responsible for voluntary movements?

Skeletal muscle cells.

What is the primary function of nervous tissue?

To coordinate and control many body activities.

What are the two main components of nervous tissue?

Neurons and glial cells.

What are the three parts of a neuron?

Cell body, dendrites, and axon.

What type of muscle forms the walls of hollow organs and is not striated?

Smooth muscle.

What are the characteristics of smooth muscle cells?

They are tapered at each end, have a single nucleus, and are not striated.

What is a tissue membrane?

A thin sheet or layer of tissue that covers a structure or lines a cavity.

What are the four types of tissue membranes in the body?

Cutaneous, mucous, serous, and synovial.

What is the cutaneous membrane?

The skin, which is an external body surface membrane.

What do mucous membranes line?

Cavities that open to the outside of the body, such as the digestive, respiratory, and reproductive tracts.

What is the composition of mucous membranes?

Epithelial cells, their basement membrane, and a thick layer of loose connective tissue.

What are the functions of mucous membranes?

Protection, absorption, and secretion.

What do serous membranes line?

Cavities that do not open to the exterior of the body, such as the pericardial, pleural, and peritoneal cavities.