Ch 4 - The Tissue Level of Organization

Question 1

tissue

Answer 1

a group of cells that usually have a common origin in an embryo and function together to carry out specialized activities

Question 2

histology

Answer 2

the science that deals with the study of tissues

Question 3

pathologist

Answer 3

a physician who examines cells and tissues to help other physicians make accurate diagnoses

specialist in the study of diseases

Question 4

epithelial tissue

Answer 4

AKA Epithelium

Cells are arranged in sheets

Cells are densely packed

Many cell junctions are present

Epithelial cells attach to a basement membrane

Epithelial tissue is avascular but does have a nerve supply

Mitosis occurs frequently

Question 5

connective tissue

Answer 5

protects and supports the body and its organs. Various types of connective tissues bind organs together, store energy reserves as fat, and help provide the body with immunity to disease-causing organisms.

Question 6

muscular tissue

Answer 6

composed of cells specialized for contraction and generation of force. In the process, muscular tissue generates hear that warms the body.

Question 7

nervous tissue

Answer 7

detects changes in a variety of conditions inside and outside the body and responds by generating electrical signals called nerve action potentials (nerve impulses) that activate muscular contractions and glandular secretions.

Question 8

biopsy

Answer 8

the removal of a sample of living tissue for microscopic examination

Question 9

cell junctions

Answer 9

contact points between the plasma membranes of tissue cells

Question 10

tight junctions

Answer 10

web-like strands of transmembrane proteins that fuse together the outer surfaces of adjacent plasma membranes to seal off passage ways between adjacent cells

prevent contents of organs from leaking into blood or surrounding tissue

common in: stomach, intestines, urinary bladder

Question 11

adherens junctions

Answer 11

contain plaque (dense layer of proteins), cadherins join the cells, usually forms an adhesion belt

Plaque attaches to membrane proteins and microfilaments

Great at resisting separation during contractile activities

Ex. Food moving through intestines

Question 12

desmosomes

Answer 12

similar to adherens junctions (have plaque and cadherens), plaque attaches to intermediate filaments of cytoskeletol (keratin), spot weld-like junctions, contribute to stability

common in: epidermis, cardiac muscle cells

Question 13

hemidesmosomes

Answer 13

look like half of a desmosome but DO NOT link adjacent cells, their transmembrane glycoproteins are integrins NOT cadherins, anchor cells NOT to each other but to the basement membrane

Question 14

gap junctions

Answer 14

connexins form tiny tunnels called connexons, plasma membranes are NOT connected but are separated by a gap

Ions and small molecules diffuse through connexons to the next cell

Question 15

apical (free) surface

Answer 15

may contain microvilli or cilia

Question 16

basal surface

Answer 16

opposite the apical surface

Question 17

basement membrane

Answer 17

a thin extracellular layer that commonly consists of two layers, the basal lamina and reticular lamina

Question 18

covering and lining epithelium

Answer 18

forms the outer covering of the skin and some internal organs. It also forms the inner lining of blood vessels, ducts, and body cavities, and the interior of the respiratory, digestive, urinary, and reproductive systems.

Question 19

glandular epithelium

Answer 19

makes up the secreting portion of glands such as the thyroid gland, adrenal galnds, and sweat glands.

Question 20

Simple

(layer arrangement of epithelial cells)

Answer 20

single layer, for secretion, absorption, diffusion

Question 21

Pseudostratified

(layer arrangement of epithelial cells)

Answer 21

appears to have multiple layers because NOT all cells reach apical surface

ALL of its cells rest on the basement membrane

nuclei are at different levels