A&P exam 2 study questions

Cell cycle

Series of changes a cell undergoes from formation to reproduction

Centrosomes

Form the mitotic spindle during prophase

Interphase and mitotic phase

The two major periods of the cell cycle

Interphase

Period when the cell carries out routine activities and prepares for division

S (synthetic) phase

Phase of interphase when DNA replication occurs

New nuclear membranes

Form around each chromatin mass during telophase

Avascularity

Characteristic meaning epithelium lacks blood vessels

Apical surface

Faces the lumen or external environment

Tight junctions (zona occludens)

Junctions found on the lateral surface of epithelial cells

Simple cuboidal epithelium

Associated with absorption, secretion, and excretion

Diffusion from underlying connective tissue

How epithelium receives nourishment

Loss of apical-basal polarity and broken lateral contacts

Stimulates high regenerative capacities in epithelial cells

Simple columnar epithelium

Cells are taller than they are wide

Goblet cells

Mucus-secreting cells found in some epithelia

Pseudostratified columnar epithelium

Appears multilayered but is not, often with cilia and goblet cells

Endocrine glands

Release secretions into surrounding interstitial fluid

Stratified squamous keratinized epithelium

Type of epithelium covering thin skin

Keratinization

Provides protection from abrasion and dehydration

Microvilli and cilia

Associated with the apical surface

Thick skin

Found on the palmar and plantar surfaces of the hands and feet

Basement membrane

Layer separating epithelium from underlying connective tissue

Simple squamous epithelium

Single layer of flattened cells

Simple squamous epithelium

Facilitates transfer of gases, fluids, and nutrients due to its thinness

Stratified cuboidal epithelium

Most often found in ducts of exocrine glands

Anaphase

Phase in which centromeres split

Hemidesmosomes

Attach the basal surface of epithelial cells to the basement membrane

Cytokinesis

Begins during late anaphase and continues through mitosis

Contact inhibition

Normal cells stop dividing when they touch

G1 checkpoint (restriction point)

Most important checkpoint in the cell cycle

Endothelium

Epithelium lining blood vessels, the heart, and lymphatic vessels

G0 phase

Cells permanently cease dividing

Early prophase

Chromatin condenses into visible chromosomes

Centromere

Holds sister chromatids together

Functions of epithelium

Protection, Absorption, Filtration, Excretion, Secretion, Sensory reception

Metaphase plate

Imaginary plane midway between cell poles

Anaphase

Shortest phase of cell division

Stratified cuboidal epithelium

Most often has two layers of cells

Increased surface area for absorption

Primary characteristic of simple columnar epithelium with microvilli

Hormones

Messenger chemicals secreted by endocrine glands

Lymph or blood

Pathway endocrine secretions travel to reach target organs

Exocrine glands

Release secretions onto body surfaces or into body cavities

Exocrine glands

More numerous type of gland

Exocrine gland secretions

Mucous, sweat, oil, and saliva

Mucous cells and goblet cells

Important unicellular exocrine glands

Unicellular exocrine glands

Found in epithelial linings of intestinal and respiratory tracts

Mucin

Produced by mucous cells and goblet cells

Mucin

Sugar-protein that forms mucus

Simple glands

Have unbranched ducts

Compound glands

Have branched ducts

Tubular gland

Secretory cells form the duct

Alveolar glands

Secretory cells form sacs

Merocrine glands

Secrete products by exocytosis as they are produced

Merocrine gland secretions

Sweat and pancreatic secretions

Holocrine glands

Accumulate products within the cell, then rupture

Sebaceous oil glands

Example of a holocrine gland

Apocrine gland secretion

Products accumulate within the cell, but only the apex ruptures

Apocrine glands

Type of gland with controversial existence in humans

Alveolar glands

Glands with secretory cells forming sacs

Tubuloalveolar glands

Glands with both secretory cells forming ducts and sacs

Unicellular exocrine glands

Mucous cells and goblet cells

Multicellular exocrine glands

Sweat glands and salivary glands

Merocrine vs holocrine secretion

Merocrine uses exocytosis, holocrine involves cell rupture

Pancreas

Secretes its products by the merocrine method