chapter five: cellular junctions, glands, and membranes & tissue growth, development, repair, and degeneration

Question 1

What are cellular junctions?

Answer 1

the connections between one cell and another

Question 2

What are three functions that cellular junctions serve?

Answer 2

enable cells to resist stress, communicate with each other, and control movement of substances through tissues

Question 3

What are the four cellular junctions?

Answer 3

tight junctions
desmosome
gap junctions
hemidesmosome

Question 4

What are tight junctions?

Answer 4

junctions that join cells tightly to their neighboring cells, sealing off intracellular space

Question 5

What links two cells together in tight junctions?

Answer 5

cell-adhesion proteins

Question 6

How does the structure of tight junctions affect diffusion of substances?

Answer 6

tight junctions make it hard for substances to pass between cells, so nutrients pass through epithelial cells

Question 7

What is one example of tight junctions in the body?

Answer 7

there are tight junctions in the stomach and intestines which prevent digestive juices from seeping between epithelial cells and digesting underlying connective tissue

Question 8

What are desmosomes?

Answer 8

junctions that mechanically link two cells together

Question 9

How does the structure of desmosomes affect diffusion of substances?

Answer 9

since the cells linked by desmosomes are not joined tightly together, substances can pass between cells

Question 10

What is the main function of desmosomes?

Answer 10

serve to keep cells from pulling apart and enable tissues to resist stress

Question 11

What is one example of desmosomes in the body?

Answer 11

cardiac muscle

Question 12

What are hemidesmosomes?

Answer 12

junctions that link the basal cells of an epithelium to underlying basement membrane

Question 13

What do hemidesmosomes prevent?

Answer 13

prevent epithelium from easily peeling away from the underlying connective tissue

Question 14

What are gap junctions?

Answer 14

a junction formed by a connexon surrounding a water-filled channel that connect the cytoplasm of two cells

Question 15

What passes through the channel of gap junctions?

Answer 15

solutes, ions, glucose, amino acids

Question 16

What is one example of gap junctions in the body?

Answer 16

in cardiac muscle, gap junctions allow electrical excitation to pass directly from cell to cell so that cells can contract in near unison

Question 17

What are glands?

Answer 17

a cell or organ that secretes substances for use elsewhere in the body or for elimination as waste

Question 18

What is secretion?

Answer 18

a useful product for the body like enzymes and hormones

Question 19

What is excretion?

Answer 19

a waste product like urine and bile that will be eliminated from the body

Question 20

What are unicellular glands?

Answer 20

secretory cells found in epithelium that is mainly nonsecretory

Question 21

What are the two types of glands?

Answer 21

exocrine and endocrine

Question 22

What are exocrine glands?

Answer 22

glands that maintain contact with the surface via a duct

Question 23

How do exocrine glands secrete its products?

Answer 23

secretes its products onto the body surface or into another organ

Question 24

What glands are sweat glands?

Answer 24

exocrine

Question 25

What are endocrine glands?

Answer 25

glands that lose contact with surface and does not have ducts

Question 26

How do endocrine glands release its products?

Answer 26

release its products directly into the bloodstream

Question 27

Do endocrine or exocrine glands have a high-density of blood capillaries.

Answer 27

endocrine

Question 28

What are the secretions of endocrine glands called?

Answer 28

hormones

Question 29

What are hormones?

Answer 29

chemical messengers that stimulate cells elsewhere in the body

Question 30

What are three endocrine glands?

Answer 30

pituitary thyroid adrenal

Question 31

What are exocrine glands enclosed in?

Answer 31

fibrous capsule

Question 32

What is the septa of exocrine glands?

Answer 32

extensions from the capsule that divide the interior into lobes

Question 33

What is the stroma of exocrine glands?

Answer 33

connective tissue framework that supports and organizes the gland

Question 34

What is the parenchyma?

Answer 34

the tissue that performs the main physiological functions of an organ

Question 35

What is the parenchyma of exocrine glands?

Answer 35

secretory acini

Question 36

What is the acinus of exocrine glands?

Answer 36

the secretory portion; a sac of secretory cells at the inner end of a gland

Question 37

What is the structure of simple coiled tubular glands?

Answer 37

single, unbranched duct

Question 38

What is the structure of compound acinar gland?

Answer 38

branched duct

Question 39

What is the structure of compound tubuloacinar?

Answer 39

secretory cells are in both the tubular and acinar portions

Question 40

What are the three types of secretions?

Answer 40

serous glands mucous glands mixed glands

Question 41

What do serous glands produce?

Answer 41

produce thin, watery fluids such as perspiration, milk, tears, and digestive juices

Question 42

What do mucous glands secrete?

Answer 42

mucin

Question 43

What does mucin do after secretion?

Answer 43

after secretion, mucin absorbs water and forms mucus

Question 44

What are mixed glands?

Answer 44

glands that contain both serous and mucous cells

Question 45

What do mixed glands produce?

Answer 45

produce a mixture of the two types of secretions

Question 46

What are the three modes of secretions?

Answer 46

eccrine gland aprocrine glands holocrine glands

Question 47

How do eccrine glands release their contents?

Answer 47

exocytosis

Question 48

How do aprocrine glands release their products?

Answer 48

form secretory vesicles that bud from the apical cytoplasm of the cell

Question 49

How do holocrine glands release their secretions?

Answer 49

cells accumulate a product and then breakdown, becoming the secretion

Question 50

What is the largest membrane of the body?

Answer 50

cutaneous membrane

Question 51

What is the cutaneous membrane?

Answer 51

the skin; consists of a stratified squamous epithelium (epidermis) resting on a layer of connective tissue (dermis)

Question 52

What are the two kinds of internal membranes?

Answer 52

mucous membrane serous membrane

Question 53

What are some functions of mucous membranes?

Answer 53

membranes have absorptive, secretory, and protective functions

Question 54

What does mucous membranes line?

Answer 54

lines passages that open to the exterior environment

Question 55

What are the three layers of mucous membranes?

Answer 55

epithelium lamina propria (areolar connective tissue) muscularis mucosae (smooth muscle)

Question 56

What does mucous membranes secrete?

Answer 56

mucus

Question 57

What do serous membranes line?

Answer 57

lines the inside of body cavities and forms a smooth outer surface on viscera (internal organs)

Question 58

What is the mesothelium?

Answer 58

the epithelia lining body cavities

Question 59

What is the endothelium?

Answer 59

the epithelia that lines blood-filled spaces

Question 60

What is hyperplasia?

Answer 60

the growth of tissue through cellular multiplication

Question 61

What is hypertrophy?

Answer 61

the growth of tissue through cellular enlargement of preexisting cells

Question 62

What is neoplasia?

Answer 62

abnormal growth of new tissue like a tumor

Question 63

What are tissues capable of?

Answer 63

tissues are capable of changing from one type to another

Question 64

What is differentiation?

Answer 64

the development of an unspecialized cell or tissue into a specialized one

Question 65

What is metaplasia?

Answer 65

transformation of one mature tissue type to another

Question 66

What are stem cells?

Answer 66

undifferentiated cells that can divide and differentiate into more functionally specific cell types

Question 67

What is developmental plasticity in stem cells?

Answer 67

the type of mature cells stem cells can become

Question 68

What are the two types of stem cells?

Answer 68

embryonic stem cells adult stem cells

Question 69

What are embryonic stem cells?

Answer 69

compose the early human embryo

Question 70

What are the two types of embryonic stem cells?

Answer 70

totipotent stem cells pluripotent stem cells

Question 71

What are totipotent stem cells?

Answer 71

cells that have the potential to develop into any type of human cells and can develop into cells of temporary structures of pregnancy

Question 72

Do totipotent stem cells have unlimited developmental plasticity?

Answer 72

yes

Question 73

What are pluripotent stem cells?

Answer 73

cells that can develop into any cell type, but not into the accessory organs of pregnancy so they have limited developmental plasticity

Question 74

What are adult stem cells?

Answer 74

occur in smaller numbers in mature organs and tissues

Question 75

How do stem cells divide mitotically?

Answer 75

one daughter cell remains a stem cell the other daughter cell differentiates into a mature specialized cell

Question 76

What is a multipoint stem adult cell?

Answer 76

a stem cell that has the potential to develop into two or more fully functional cells

Question 77

What is a unipotent adult stem cell?

Answer 77

stem cells that have the potential to develop into only one fully functional cell

Question 78

Do multipotent stem cells or unipotent stem cells have the most limited plasticity?

Answer 78

unipotent stem cells

Question 79

What are the two ways tissues can be repaired?

Answer 79

regeneration and fibrosis

Question 80

What is regeneration?

Answer 80

the replacement of dead or damaged tissue with new tissue of the original type

Question 81

What is one example of regeneration?

Answer 81

most skin injuries: cuts, scrapes, minor burns

Question 82

What is fibrosis?

Answer 82

the replacement of damaged tissue with fibrous scar tissue

Question 83

What is the purpose of scar tissue?

Answer 83

scar tissue helps hold an organ together, but does not restore normal function

Question 84

What is atrophy?

Answer 84

the shrinkage of tissue through loss of cell size or number

Question 85

What can atrophy result from?

Answer 85

normal aging (senile atrophy) lack of use of an organ (disuse atrophy)

Question 86

What is necrosis?

Answer 86

premature, pathological tissue death due to infection, trauma, toxins, etc.

Question 87

What are the two types of necrosis?

Answer 87

infarction and gangrene

Question 88

What is infarction?

Answer 88

the sudden death of a tissue from lack of blood flow/blood is cut off

Question 89

What is gangrene?

Answer 89

tissue death due to ischemia (obstructed blood supply) or infection

Question 90

What is apoptosis?

Answer 90

programmed cell death; the normal death of cells