Exam 4 tissues bio

What is a tissue?

A tissue is a group of associated cells performing a common function.

What are the four main types of tissues in the human body?

Epithelial, connective, muscle, and nervous tissues

What is the function of nervous tissue?

It transmits electrical impulses for communication and control of the body's actives.

Where is nervous tissue found?

In the brain, spinal cord, and nerves.

What is the main function of muscle tissue?

Producing body movement through contraction.

What are the three types of muscle tissue?

Skeletal, smooth, and cardiac muscle tissue.

What is the function of epithelial tissue?

It covers body surfaces, lines cavities, and forms glands for protection, secretion, and absorption.

What is connective tissue responsible for?

Supporting and connecting other tissues and organs in the body.

What are the main characteristics of epithelial tissue?

It has closely packed cells, little extacellular material, avascularity, and a high rate of regeneration

What are the main functions of epithelial tissue?

Protection, secretion, absorption, filtration, and sensory reception

What are the two main types of epithelial tissue?

Covering and lining epithelium, and glandular epithelium.

What is glandular epithelium specialized for?

Secretion of hormones, mucus, and enzymes

What are the three shapes of epithelial cells?

Squamous(flat), cuboidal(cube-shaped), and columnar(tall)

What are the two main arrangements (layers) of epithelial tissue?

Simple(one layer) and stratified(multiple layers)

What is pseudstratified epithelium?

A type of epithelium that appears to have multiple layers but actually only has one, with nuclei at different height.

What is transitional epithelium, and where is it found?

It allows stretching and is found in the urinary bladder.

How does epithelial tissue protect the body?

It forms a barrier against mechanical injury, pathogens, and fluid loss.

What epithelial function allows for the secretion of hormones and mucus?

Glandular secretion

How does epithelial tissue help with absorption?

Specialized cells absorb nutrients in organs such as the intestines

What is the function of cilia on epithelial cells?

To move substances such as mucus or productive cells across the surface.

What are tight junctions?

They form seals between cells to prevent leakage of materials.

What are desmosomes?

They anchor cells together for structural support.

What are gap junctions?

Channels that allow communication and transfer of ions or small molecules between cells.

What are microvilli and what is their function.

Small projections that increase surface area for absorption.

What is the basement membrane?

A thin layer that attaches epithelial tissue to underlying connective tissue.

What are the main functions of epithelial tissue?

Protection, absorption, filtration, secretion, and sensation.

What are the two major types of epithelial tissue?

Covering/lining epithelium and glandular epithelium.

How are epithelial tissues classified?

By the number of layers and the shape of cells.

What is simple epithelium?

A single layer of cells involved in absorption, secretion, or filtration.

What is stratified epithelium?

Multiple layers of cells providing protection against abrasion.

Describe simple squamous epithelium and where its found

Single flat cells; allows diffusion and filtration. Found in air sacs of lungs and lining of blood vessels.

What is the function of simple cuboidal epithelium?

Secretion and absorption. Found in glands and kidney tubules.

What is simple columnar epithelium specialized for?

Absorption and secretion; may have microvilli or cilia. Found in the digestive system.

What is pseudostratified columnar epithelium?

Appears multilayered but all cells touch the basement membrane. Often ciliated and lines the respiratory tract.

What is stratified squamous epithelium and what are its types?

Multiple layers of flat cells for protection.

keratinized: surface cells are dead and filled with keratin(skin).

non-keratinized: moist surfaces like mouth, esophagus, vagina

What is stratified cuboidal/columnar epithelium found?

Rare; found in ducts of large glands (sweat glands)

What is the main function of transitional epithelium?

Stretching to accommodate fluctuation in organ size(urinary bladder)

What are the two types of glands based on where they secrete?

Endocrine glands: Secrete hormones directly into the blood

Exocrine glands: secrete substances onto body surfaces or into ducts.

Examples of endocrine glands

thyroid, adrenal glands

Examples of exocrine glands

sweat, salivary, sebaceous glands

What are unicellular glands?

single cells like goblet cells

What are multicellualr glands?

Consist of a duct and secretory unit (simple or compound)

What are the three types of secretion mechanisms i exocrine glands?

Merocrine- secretion via exocytosis (salivary glands)

Apocrine- part of the cell pinches off with secretion (mammory glands)

Holocrine- entire cell ruptures, releasing product (sebaceous glands)

What are the main functions of connective tissue?

Binding and support, protection, insulation, and transportation of substances

What are the three structural components of connective tissue?

Ground substance, fibers, and cells

What are the types of fibers found in conective tissue?

Collagen(strength), elastic(stretch/recoil), and reticular(support)

What types of cells are found in connective tissue?

Fibroblasts, chondrocytes, osteocytes. adipocytes, macrophages, and white blood cells

What are the two main types of connective tissue ?

Loose connective tissue and dense connective tissue

What are the types and functions of loose connectice tissue?

Areolar-supports and binds tissue, holds fluids, stores nutrients.

Adipose-stores fat, insulates, and cushions organs

Reticular- supports free blood cells in lymphoid organs(spleen, lymth nodes)

Dense regular connective tissue

Parallel collagen fibers; resis tensions (tendons, ligaments)

Dense irregular connective tissue

irregularly arranged collagen; provides strength in multiple directions (dermis, joint capsules)

Elastic connective tissue

High content of elastic fibers; allows stretch(large arteries, liagaments)

What are the main features of cartilage?

Tough yet flexible; avascular; cells are chondrocytes in lacunae; matrix with collagen and elastic fibers

hyaline cartilage

most common cartilage, supports and reinforces (nose, trachea, ends of bones)

elastic cartilage

provides flexibility(external ear,epiglottis)

fibrocartilage

strong, resists compression (intervertebral discs, pubic symphysis)

What are the two types of bone tissue?

Compact bone and spongy bone

What are bone cells called?

Osteocytes

What are the functions of bone tissue?

Support, protection, storage of calcium, and blood cell formation(hematopoiesis)

What type of tissue is blood classified as?

A connective tissue with a liquid extracellualr matrix(plasma)

What are the main components of blood?

Plasma, red blood cells(erythrocytes), white blood cells(leukocytes), and platelets(thrombocytes)

What are the functions of blood?

Transport gases, nutrients, and wastes; defense; and regulation

What are the three types of muscle tissue?

Skeletal, cardiac, and smooth muscle

What is the function of muscle tissue?

Movement through contraction

What type of muscle tissue is involuntary and found in the walls of hollow internal organs?

smooth muscle(non-striated, involuntary)

What is the main function of smooth muscle?

Moves substances along tracts, changes diameter of blood vessels, and aids in regulation of blood pressure

Which type of muscle is striated and involuntary, making up the walls of the heart?

Cardiac muscle

What structures in cardiac muscle allows direct communication between cells?

Intercalated discs

What is the primary function of nervous tissue?

Rapidly regulates and intergrates activities of different body parts; transmits messages via electrical impulses

What are the supportive cells in nervous tissue called, what do they do?

Neuroglia; they connect and protect neurons

What is the cell body part of a neuron called?

soma

Which neuron processes carry impulses away from the soma?

Axon

Which neuron processes carry impulses toward the soma?

dendrites

What happens to tissues when they are damaged?

They undergo regeneration; phagocytic cells remove dead/injured cells, and other cells divide to repair the wound.

What are the two major layers of body membranes?

Superficial layer(epithelial) and deep layer (connective tissue)

What are the three types of epithelial membranes?

Cutaneous, serous, and mucous membranes

What is the main function of cutaneous membranes?

Protects the body; contains sweat and oil glands producing a surface film

What do serous membranes do?

Line body cavities not open to the exterior; cover organs inside cavities; reduce friction

What is the difference between parietal and visceral membranes?

Parietal lines cavity walls; visceral covers surfaces of organs

What are mucous membranes, and where are they found?

Epithelial membranes lining body surfaces open to the exterior, e.g. respiratory, digestive, urinary, and reproductive tracts. They produce mucus to protect cells and act as lubricants.

What are connective tissue membranes, and what is their role?

Membranes without epithelial layers; line spaces between bones/joints; secretes synovial fluid to reduce friction and lubricate joints

What type of connective tissue forms the framework of soft organs like the spleen or liver?

Reticular connective tissue

What type of connective tissue makes up tendons and ligaments?

Dense regular connective tissue