exam #2 Flashcards
1
Q
histology
A
the study of tissues, especially with a microscope
2
Q
tissues
A
-aggregation of similar cells, their products, and materials surrounding
-have specific structure and function
3
Q
tissue components
A
cells and extracellular matrix (ECM)
4
Q
extracellular matrix (ECM): components
A
-varies by tissue type
-extracellular fluid: mostly water
-proteins
—glycoproteins attached to plasma membrane
—fibrous proteins: long, thin proteins like collagen
—proteoglycans: enormous carbohydrates with multiple protein-carbohydrate attachments
5
Q
extracellular matrix (ECM): functions
A
-protection of cells
-holds cells together
-facilitates cellular communication
6
Q
extracellular matrix (ECM): other names
A
-interstitial fluid
-tissue fluid
7
Q
four principle tissues
A
epithelial, connective, nervous, muscular
8
Q
types of epithelial tissue
A
-simple
-stratified
9
Q
types of connective tissue
A
-fibrous
-cartilage
-bone
-blood
10
Q
types of muscle tissue
A
-skeletal
-smooth
-cardiac
11
Q
epithelial tissue
-definition
-representative locations
A
-tissue composed of layers of closely spaced cells that cover organ surfaces, form glands, and serve for protection, secretion, and absorption
-epidermis, inner lining of digestive tract, liver and other glands
12
Q
connective tissue
-definition
-representative locations
A
-tissue with usually more matrix than cell volume, often specialized to support and protect organs and to bind other tissues and organs to each other
-tendons and ligaments, cartilage and bone, blood
13
Q
nervous tissue
-definition
-representative locations
A
-tissue containing excitable cells specialized for rapid transmission of coded information to other cells
-brain, spinal cord, nerves
14
Q
muscle tissue
-definition
-representative locations
A
-tissue composed of elongated, excitable muscle cells specialized for contraction
-skeletal muscles, heart (cardiac muscle), walls of viscera (smooth muscle)
15
Q
types of simple epithelial tissues
A
-simple squamos
-simple cuboidal
-simple columnar
-pseudostratified columnar
16
Q
types of stratified epithelial tissues
A
-stratified squamos
-stratified cuboidal
-stratified columnar
-transitional
17
Q
types of fibrous connective tissue
A
-loose fibrous connective tissue: areolar, reticular, adipose
-dense fibrous connective tissue: dense regular, dense irregular, elastic
18
Q
types of cartilage connective tissue
A
-hyaline
-elastic
-fibrocartilage
19
Q
types of bone connective tissue
A
-spongey
-compact
20
Q
cells in tissues, especially epithelial tissues, often are joined together by ____
A
junctions
21
Q
junction functions
A
-bind cells together
-allow near instant cell to cell communication
22
Q
typical junction locations
A
-lateral surface: side of cells
-basal surface: bottom of cell
23
Q
types of cellular junctions
A
-tight junctions
-desmosomes
-hemidesmosomes
-gap junctions
24
Q
tight junctions
A
-tightly joins epithelial cells near apical surface
-seals space between cells: prevents fluids squeezing between cells and bacterial invasion
-weak: can be broken easily
25
desmosomes
-holds cells together
-strong: resists mechanical stress
-loose, not continuous like tight junctions
26
hemidesmosomes
-half-desmosomes
-bind basal cells of epithelial tissue to underlying fibers (basement membrane)
-prevents cells from peeling away
27
gap junctions
-aka communicating junction
-6 proteins forming a large channel
-solutes and water pass through cell to cell
-allows near-instant communication
-common in smooth and cardiac muscle
28
tissues grow by?
-hyperplasia
-hypertrophy
increasing in cell number or size
-hyperplasia: growth due to increase in cell number
-hypertrophy: growth due to increase in cell size
29
stem cells
-embryonic stem cells
---totipotent
---pluripotent
-adult stem cells
---multipotent
---unipotent
stem cells: differentiate to give rise to cell/tissue types
-embryonic stem cells: give rise to ALL cell types
---totipotent: can become all adult cell types and placenta cells
---pluripotent: can become all adult cell types
-adult stem cells: give rise to 1 or a small number of cell types
---multipotent: a few types
---unipotent: 1 type
30
atrophy
-caused by?
atrophy = loss of cell size
-caused by disuse and/or aging
31
apoptosis
-functions
apoptosis = planned loss of cell number
-programmed cell death
-non-inflammatory
-functions:
---organ development: removing excess cells
---normal maintenance: cycling out older/damaged cells
32
necrosis
necrosis: death of cells
-due to lack of blood supply or damage
-inflammatory
-not always reversible
33
regeneration
-replacing dead cells with cells of same type
-restores organ function
34
fibrosis
-replacing dead cells with scar tissue- mostly fibrous proteins like collagen
-does not fully restore organ function
-faster, requires fewer resources
35
tissue death and degeneration: 3 types
atrophy, apoptosis, necrosis
36
tissue repair: 2 types
regeneration and fibrosis
37
epithelial tissue (epithelium): what it is
-closely adhering cells, one or more layers thick
-almost no extracellular matrix
38
epithelial tissue (epithelium): functions
-line organs, form glands
-protection, secretion, absorption, filtration and/or sensation
39
epithelial tissue (epithelium): characteristics
-cells polar/nonpolar
-cells loosely/tightly packed
-blood vessels?
-nerves?
-heal via?
-supported by?
-cell polarity: cells are not perfectly symmetrical
---apical surface: upper, basal surface: lower, lateral surface: side
-cells closely packed: many tight junctions and desmosomes
-avascular: no blood vessels
-innervated: nerves are present
-heal mostly via regeneration
-support by connective tissue: just superficial to connective tissue usually
40
epithelial classifications
-based on?
number of cell layers
-1 layer = simple
-2 or more layers = stratified
-looks like multiple layers, but not = pseudostratified
cell shape
-flat, scaly = squamos
-cube = cuboidal
-rectangular = columnar
41
epithelial tissue type: simple squamous
-single layer of flat cells
-used for rapid diffusion between areas
42
epithelial tissue type: simple cuboidal
-single layer of square cells
-forms ducts (tubes) and glands
43
epithelial tissue type: simple columnar
-single layer of tall cells
-lines lumen (hollow center) of organs
-useful for absorption (esp in digestive tract)
44
epithelial tissue type: pseudostratified columnar
-single layer of tall cells that looks multi-layered
-lines respiratory tract
45
epithelial tissue type: stratified squamous
-many layers of flat cells
-found in skin- provides great protection
46
epithelial tissue type: stratified columnar
-many layers of tall cells
-almost never seen
47
epithelial tissue type: stratified cuboidal
-many layers of square cells
-found in some ducts (sweat)
48
connective tissue characteristics
-tissue in which cells occupy less space than extracellular matrix
-cells usually do not directly contact one another
-most abundant, distributed, variable tissue type
-varying vascularity
49
connective tissue functions (7)
-binding/connecting
-support
-protection: physical and immunity
-movement
-storage
-heat protection
-transport
50
connective tissue cell name suffixes
-blasts: create the extracellular matrix
---fibroblast: makes collagen fibers
-clasts: break down extracellular matrix for modeling
---osteoclast: breaks down bone matrix
-cytes: maintain extracellular matrix
---chondrocyte: maintains cartilage
51
fibrous connective tissue: what it is
-aka connective tissue proper
-ECM contains many fibrous proteins (fibers) and ground substance
52
fibrous connective tissue: types
-dense fibrous connective tissue: more fibrous proteins
-loose fibrous connective tissue: fewer fibrous proteins
53
fibrous connective tissue: collagen fibers
-strong/weak? how abundant?
-provides what?
-other fiber types
-strongest and most abundant fibrous protein
-provides high tensile strength: prevents breaking/tearing
-other fiber types: reticular and elastic
54
fibrous connective tissue: ground substance
-gel-like substance made of water and proteins
-absorbs compressive forces
55
loose fibrous connective tissue: areolar tissue
-loose arrangement of collagen and elastic fibers in ground substance
-adheres epithelial tissues to other tissues
-widely distributed
56
loose fibrous connective tissue: reticular tissue
-mostly reticular fibers
-forms framework of some internal organs
57
loose fibrous connective tissue: adipose tissue
-aka fat
-mostly cells called adipocytes (probably shouldn't be classified as connective)
-stores energy, insulation, protection, heat generation
58
dense fibrous connective tissue: dense regular
-almost all parallel collagen fibers
-forms tendons and ligaments
59
dense fibrous connective tissue: dense irregular
-almost all randomly distributed collagen
-forms dermis of skin
60
cartilage connective tissue: characteristics
-cartilage: stiff connective tissue with dense, flexible, glassy matrix
-avascular
61
cartilage connective tissue: cells
-chondroblasts: produce matrix
-chondrocytes: maintain matrix, trapped in small spaces called lacunae
62
cartilage connective tissue: cartilage types
-hyaline cartilage: lines skeletal joints
-fibrocartilage: more parallel collagen fibers, forms intervertebral discs
-elastic cartilage: more elastic fibers, forms external ear
63
integument literally means?
"the outer layer"
64
organs of the integumentary system
-skin
-hair
-nails
-cutaneous glands: sweat, oil, mammary
65
integumentary system function: physical protection
protections all deeper tissues
66
integumentary system function: thermoregulation
sweat cools, hair insulates
67
integumentary system function: lipid storage
for energy, insulation
68
integumentary system function: excretion
some wastes leave the body via sweat
69
integumentary system function: sensation
skin is well innervated (contains many nerves)
70
integumentary system function: immune response
skin blocks pathogens, contains immune cells
71
integumentary system function: vitamin D regulation
skin exposure to UV is first step in forming vitamin D
72
integumentary system function: non-verbal communication
flushing of face, facial expression, "goosebumps"
73
integumentary system functions (8)
-physical protection
-thermoregulation
-lipid storage
-excretion
-sensation
-immune response
-vitamin D regulation
-non-verbal communication
74
the skin is _ layers
-name those layers and where they are
2
-epidermis = superficial
-dermis = deep
75
what is the 3rd layer of the integument?
hypodermis
-deep to dermis
-NOT a skin layer
-usually studied with the skin
76
epidermis: composition (type of tissue found here)
composed of keratinized stratified squamous epithelium
77
what does keratinized mean?
most cells are packed with the protein keratin
-keratin provides rigidity, toughness
-keratin also main protein in nails and hair
78
layers of epidermis (superficial to deep)
(Come Lets Get Sun Burned)
startum corneum
stratum lucidum
stratum granulosum
stratum spinosum
startum basale
79
thick v.s thin skin of epidermis
-found where
-key difference
-thickest layer
thin skin
-found in most places
-no stratum lucidum
-stratum spinosum is thickest layer
thick skin
-found in palms of hands and soles of feet
-stratum corneum thickest layer by far
80
cells of epidermis
-stem cells
-tactile cells
-dendritic cells
-melanocytes
-keratinocytes
81
cells of epidermis: stem cells
-divide to make?
-found where?
-divide to give rise to keratinocytes
-found only in stratum basale
82
cells of epidermis: tactile cells
-touch receptors
-found in stratum basale
-associated with nerve fiber from dermis
83
cells of epidermis: dendritic cells
-immune cells
-alert body of infection
-in stratum spinosum and stratum granulosum
84
cells of epidermis: melanocytes
-synthesize melanin: protein pigment that protects skin from UV rays
-only found in stratum basale
85
cells of epidermis: keratinocytes
-bulk of epidermis
-synthesize keratin
-found in all layers
---are slowly pushed up by new keratinocytes forming from stem cells
---oldest keratinocytes (30-40 days) are most superficial
86
epidermis layer: stratum basale
-types of epithelial cells found here
-attached to
-cell types
-keratinocytes of stratum basale
-single layer of cuboidal or columnar cells
-attached to basal lamina: layer of proteins superficial to dermis
-cell types: stem cells --> keratinocytes, melanocytes, tactile cells
-keratinocytes of stratum basale
---differentiate from stem cells
---form single layer
87
epidermis layer: stratum spinosum
-key features
-cells types
-keratinocytes of stratum spinosum
-desmosomes and tight junctions make cell look spiny
-thickest layer of thin skin
-cell types: keratinocytes, melanocytes processes (extensions from melanocytes), dendritic cells
-keratinocytes of stratum spinosum
---flatten as they are pushed upward
---accumulate melanosomes: vesicles of protein melanin made by melanocytes
88
epidermis layer: stratum granulosum
-how many layers of keratinoyctes
-how keratinocytes change appearance
-last point where?
-1-5 layers of flat keratinocytes
-keratinocytes change appearance drastically
---flatten
---produce keratin filaments
---accumualte dark keratohyalin granules
------granule = anything that looks like small specks or "grains" under a microscope
------keratohyalin granules produce proteins that bind keratin filaments together
---membrane-coating vesicles waterproof cells by releasing lipids onto cell surface
-last point where keratinocytes alive
---cells cut off from nutrients due to distance from blood supply & waterproofing --> degradation of organelles --> near death
89
epidermis layer: stratum lucidum
-appearance
-what makes this layer special?
-how many layers of keratinocytes
-clear, think layer in microscopy
-only present in thick skin
-2-3 dead keratinocyte layers
---no nuclei or organelles
---dead cells and cell fragments still bound by desmosomes
---keratohyalin granules continue bundling keratin filaments
90
epidermis layer: stratum corneum
-key features
-how many layers of keratinocytes
-most superficial
-highly keratinized, dry barrier
-thickest layer of thick skin
-up to 30 layers of flat, dead keratinocytes
---eventually keratinocytes exfoliate - many adhered cells flake off together
---dander - large sheets of exfoliated keratinocytes
91
dermis layer: papillary layer
-superficial or deep?
-made of
-papillary layer structures
-superficial
-made of areolar connective tissue
-papillary layer structures
---capillaries: blood supply of epidermis
---nerve endings: provide sensation
---most cells of dermis found here
92
dermis layer: reticular layer
-superficial or deep
-made of
-reticular layer structures
-deep
-made of dense irregular connective tissue
-reticular layer structures
---thick collagen bundles
---little ground substance
---a few fibroblasts
---occasional adipocyte clusters
93
dermis structure: border with epidermis
-how it works
-composed of
-structures formed by border
-wavy border interlocks layers, prevents slippage
-composed of alternating dermal papillae and epidermal ridges
---dermal papilla: upward projection of dermis
---epidermal ridge: downward projections of epidermis
-structures formed by border
---skin furrows: indentations made by epidermal ridges
---fingerprints: raised areas formed by dermal papillae
94
dermis structure: flexure lines
-what it is
-formed by
-where found
-where skin folds in joint movements
-formed by thinner dermis and/or less dense collagen
-most visible on palms and digits
95
dermis structure: blisters
-caused by
-how it works
-caused by forces parallel with skin damaging blood vessels in dermis
-blood plasma (AKA serum) leaks from damaged vessels, separates dermis from epidermis
96
hypodermis
-aka
-composition
-functions
-key feature
-aka "subcutaneous" tissue
-composition
---mostly adipose tissue
---some areolar tissue
-functions
---binds skin to underlying tissue
---energy reservoir
---insulation
-not a skin layer and highly vascular
---hypodermic injections target this layer
97
all skin tones caused by?
combination of three pigments: melanin, carotene, hemoglobin
98
melanin: melanosomes
-what they are
-transferred to?
---accumulate where?
---function
-vesicles where melanin is stored
-transferred to keratinocytes
---accumulate most on superficial (apical) side of keratinocyte in nucleus
---shields DNA from UV
99
melanin: impact on skin tone
-number of melanocytes
-melanin types
-melanosome production
-melanosome accumulation
-melanosome longevity
-all humans have roughly the same number of melanocytes
-melanin type
---pheomelanin: reddish-yellow
---eumelanin: brownish-black
-melanosome production: more melanosomes = darker skin
-melanosome accumulation
---distributed across keratinocyte = darker skin
---only around nucleus = lighter skin
-melanosome longevity: longer lasting = darker skin
100
melanin: freckles and moles
localized areas of melanin accumulation
-freckles: flat
-moles: raised, can contain hair follicles
101
melanin: birthmarks
-pigmented birthmarks caused by large patches of melanin accumulation
-vascular birthmarks: caused by hemoglobin
102
carotene
-yellow/orange pigment
-not produced by our own bodies, must be obtained from diet
---yellow and orange vegetables, egg yolks
-can accumulate in stratum corneum, subcutaneous fat
-most obvious in palms and soles
103
hemoglobin
-red pigment of blood
-gives melanin-poor skin pinkish hue
-makes lips red: capillaries closer to surface
-makes areas red with inflammation, increased blood flow, hematoma (bruising)
