Exam One

Question 1

eukaryotes

Answer 1

higher animals & plants, fungi, protozoa, & most algae, larger, more extensive intracellular anatomy and organization, membrane-bound intracellular compartments (organelles), well defined nucleus. Histones (bind w/ DNA and involved in supercoiling of DNA), have several chromosomes

Question 2

prokaryotes

Answer 2

cyanobacteria (blue-green algae), bacteria, and rickettsiae, contain NO organelles, and nuclear material is NOT encased by a membrane, they lack a distinct nucleus, nuclei carry genetic information in a single chromosome, lack histones

Question 3

Chemical Signaling - hormonal

Answer 3

involves specialized endocrine cells that secrete chemicals called hormones (eg. thyroid stimulating hormone); hormones are released by one set of cells & travel through the tissue & through the bloodstream to produce a response in other sets of cells

Question 4

Chemical signaling - neurohormonal

Answer 4

hormones (ie angiotensin II) are released into the blood by neurosecretory neurons. Like endocrine cells, neurosecretory neurons release blood-borne chemical messengers, whereas ordinary neurons secrete short-range neurotransmitters into a small, discrete space (synapse).

Question 5

Chemical Signaling-paracrine

Answer 5

cells secrete local chemical mediators that are quickly absorbed, destroyed, or immobilized. Paracrine signaling usually involves different cell types

Question 6

chemical signaling - autocrine

Answer 6

cells also may produce signals that they themselves respond to

Question 7

chemical signaling - neurotransmitter

Answer 7

neurons communicate directly with the cells they innervate by releasing chemicals or neurotransmitters at specialized junctions called chemical synapses; the neurotransmitter diffuses across the synaptic cleft and acts on the postsynaptic target cell.

Question 8

Passive Transport Mechanism - diffusion

Answer 8

oxygen, carbon dioxide & steroid hormones. Move from higher concentration to lower.

Question 9

Passive Transport Mechanism -filtration

Answer 9

movement of water & solutes through a membrane because of a greater pushing pressure (force) on one side of the membrane than on the other side. example= hydrostatic pressure is the blood pressure generated in vessels by the contraction of the heart. Blood reaching the capillary bed has a hydrostatic pressure 25-30 which is sufficient force to push water across the thin capillary membranes into the interstitial space.

Question 10

Passive Transport Mechanism-osmosis

Answer 10

movement of water down a concentration gradient across a semipermeable membrane from a region of higher water concentration to a region of lower water concentration

Question 11

Epithelial tissue

Answer 11

covers most internal & external surfaces of the body, variety of locations, epithelial has several diverse functions including protection, absorption, secretion & excretion. Classified 2 ways - according to the number & arrangement of cell layers and 2nd - according to cell shape. squamous are flat & thin, cuboidal appear square in vertical sections, & columnar are taller than they are wide and appear rectangular.

Question 12

Connective tissue

Answer 12

varies considerably in structure and function but is most common as the framework on which epithelial cells cluster to form organs. Other functions include binding various tissues and organs together, supporting them in their locations, and serving as storage sites for excess nutrients. Characterized by an abundant extracellular matrix that surrounds few cells.

Question 13

Muscle tissue

Answer 13

composed of long, thin cells or fibers called myocytes. Myocytes are highly contractile. 3 type of muscle tissue are skeletal, cardiac, & smooth.

Question 14

Neural tissue

Answer 14

composed of highly specialized cells call neurons, which receive and transmit electrical impulses very rapidly across junctions called synapses. Total # of neurons is fixed at birth, and replacement is impossible thereafter. They are composed of the following parts (1) a cell body (2) a single axon, & (3) one or more dendrites. Axons = Away. Dendrites conduct nerve impulses toward the body.

Question 15

Cellular adaptation - atrophy

Answer 15

decrease or shrinkage in cellular size. if atrophy occurs in a sufficient number of an organ’s cells, the entire organ shrinks or becomes atrophic. Atrophy can affect any organ but it is most common in skeletal muscle, the heart, secondary sex organs, and the brain.

Question 16

Cellular adaptation - hypertrophy

Answer 16

increase in the size of cells that consequently increases the size of the affected organ. Most of the studies of hypertrophy come from the heart.

Question 17

Cellular adaptation - dysplasia(atypical hyperplasia)

Answer 17

increase in the # of cells in an organ or tissue resulting from an increased rate of cellular division. Occurs as a response to an injury that results when the injury has been severe and prolonged.

Question 18

Cellular adaptation - metaplasia

Answer 18

reversible replacement of one mature cell type (epithelial or mesenchymal) by another, sometimes less differentiated, cell type. Found in association with tissue damage, repair, and regeneration. Develops from a reprogramming of stem cells existing in most epithelia or of undifferentiated cell present in connective tissue.