Chapter 4: Tissues Flashcards

1
Q

define histology

A

the study of tissues

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2
Q

what are the 4 major tissue types

A
  • epithelial
  • connective
  • muscular
  • nervous
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3
Q

what characteristics do all tissue types share

A
  • exist as aggregations of identical cells (sheets, lumps, etc.)
  • has a range of specific shapes, sizes, thickness, and intercellular connections
  • has unique distribution pattern throughout the body
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4
Q

what type of physician must be able to identify tissue types based on their shape, size, thickness, and cell connections

A

pathologist/histopathologist

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5
Q

define pathology and histopathology

A
  • pathology: the study of disease
  • histopathology: the study of diseased tissue
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6
Q

describe the two types of tumor growths

A
  • benign: harmless
  • malignant: harmful, cancer
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7
Q

do medical histologists use electron or light microscopes

A
  • light microscopes
  • electron microscopes are generally used for research purposes
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8
Q

what tools/equipment do histologists need to do histology

A
  • microtome
  • high quality light microscope
  • broad array of solutions and stains
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9
Q

define a microtome

A

toll used by histologists to make ultra-thin sections of tissues (1-3 cell layers)

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10
Q

why is histology important in medicine

A
  • the professional medical histologist (pathologist) examines the appearance of a sample tissue (biopsy) from a patient
  • determines if the tissue is normal or abnormal
  • essential part of diagnosis leading to proper treatment
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11
Q

what is an example of histopathology that does not require a human to examine the sample

A
  • blood tests
  • machine can view and analyze blood sample for levels and pathogens
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12
Q

briefly describe epithelial tissue

A
  • lines body surfaces (internal and external)
  • major tissue type of glands
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13
Q

define gland

A
  • structure that secretes something
  • exocrine and endocrine
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14
Q

define exocrine glands

A
  • secrete a solution, made mostly of water, that has a physiological purpose
  • secretes solution into a duct that leads to a body surface (external or internal)
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15
Q

examples of exocrine glands/secretions

A
  • sweat
  • sebaceous (oil)
  • saliva
  • semen
  • breast milk
  • pancreatic enzymes in small intestine that breakdown macromolecules and neutralize stomach acid
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16
Q

what do all exocrine glands HAVE to have

A

a duct/tube that leads secretions to surface

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17
Q

define endocrine glands

A
  • produce an organic molecule called a hormone that is secreted into the bloodstream (no duct needed)
  • sent to all body tissues, effects cells with that hormones’ receptors
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18
Q

define hormone

A
  • organic molecule
  • chemical message
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19
Q

what organ has both exocrine and endocrine glands

A

pancreas

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20
Q

is insulin secreted from an exocrine or endocrine gland

A

endocrine

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21
Q

briefly describe connective tissue

A
  • tissue with a connection function
  • internally binds tissues within an organ
  • connects organs to each other and to the body wall
  • found everywhere in the body
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22
Q

what is the most abundant tissue type

A
  • connective tissue
  • almost all organs have some connective tissue
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23
Q

briefly describe muscle tissue

A
  • rapidly shortens producing force
  • major tissue type of the muscular system
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24
Q

how does muscle tissue produce force

A
  • rapidly shortening
  • more cells shortening = more force
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25
Q

briefly describe nervous tissue

A
  • major tissue type of the nervous system
  • cells convey electrochemical signals for sensing, decision making, and control or support those that do
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26
Q

examples of senses of the nervous system

A
  • the 5 senses: sight, smell, touch, taste, vision
  • pain
  • temperature
  • pressure
  • vibration
  • etc.
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27
Q

describe the structure of epithelial tissue

A
  • cells take up max volume, minimal extracellular space
  • has basal and apical surface
  • desmosomes connect adjacent cells
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28
Q

define basal surface and apical surface

A
  • basal: attached to thin fibrous basement membrane
  • apical: faces the void
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29
Q

describe desmosomes

A
  • specialized connections between adjacent cells
  • proteins tethering cells together
  • half of a desmosome is in each adjacent cell, the halves connect to join cells
  • intermediate filaments attach to the desmosomes inside cells
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30
Q

describe hemidesmosomes

A
  • attaches cell to basement membrane
  • half of a desmosome on the bottom of the cell
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31
Q

why is it important for epithelial cells to have desmosome connections

A
  • epithelial tissue lines body surfaces so it needs reinforcement
  • must be able to keep outside stuff out and inside stuff in
  • extra reinforcement needed to limit the effects of frictional forces that happen on areas where epithelial tissue is present
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32
Q

what are the 5 functions of epithelial tissue

A
  • mechanical protection
  • barrier for chemicals and small particles
  • passage of certain molecules
  • synthesize and secrete molecules or solutions (glands)
  • absorption (simple columnar cells in intestinal lining)
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33
Q

describe how epithelial tissue provides mechanical protection

A

50+ layers of keratinized cells in the epidermis protect underlying structures from abrasion/friction

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34
Q

describe how epithelial tissue is a barrier for chemicals and small particles

A
  • tight connections of cells in the epidermis protect from pathogen invasion
  • keratinized skin cells act as a water-resistant barrier to keep water from leaking out through the skin
35
Q

describe how epithelial tissue functions as passage for certain molecules

A
  • epithelial cells line the alveoli air sacs in the lungs
  • simple squamous epithelial cells allow for the diffusion of oxygen and carbon dioxide into the bloodstream
36
Q

why are alveoli important

A
  • allow for diffusion of oxygen and carbon dioxide
  • increase the surface area of the lungs to allow for more diffusion (surface area the size of a tennis court)
37
Q

describe the structure of connective tissue

A
  • cells inhabit a relatively small volume
  • much of the volume found between cells in the extracellular matrix
38
Q

what does the extracellular matrix of connective tissue include

A
  • collagen fibers
  • reticular fibers
  • elastin fibers
  • ground substance
  • interstitial fluid
39
Q

what is the ground substance of the extracellular matrix of connective tissue composed of

A

proteins and carbohydrates that are not fibrous

40
Q

what are the 6 functions of connective tissue

A
  • binding
  • support and movement
  • storage
  • padding and insulation
  • transport
  • protection
41
Q

describe how connective tissue functions by binding

A

connective tissue binds the tissues within an organ, organs to one another, and organs to the body wall

42
Q

describe how connective tissue functions in support and movement

A
  • essential for the musculoskeletal system to execute core functions
  • tendons and ligaments are made of dense regular connective tissue
43
Q

what type of tissue are tendons and ligaments made of

A

dense regular connective tissue

44
Q

define tendons and ligaments

A
  • tendons: connect muscle to bone
  • ligaments: connect bone to bone
45
Q

are bones and muscles organs

A

yes

46
Q

how many bones are in the skeletal system

A

206

47
Q

describe how connective tissue functions in storage

A
  • bone tissue stores calcium and phosphate
  • adipose tissue stores fat
48
Q

describe the purpose of calcium and phosphate in bones

A
  • used to make bones rigid and hard
  • stored in the bones, can be released from the bone when needed elsewhere in the body
49
Q

describe how connective tissue functions in padding and insulation

A
  • adipose tissue
  • subcutaneous fat insulates the whole body
50
Q

describe how connective tissue functions in transport

A
  • blood is a connective tissue, connects all tissues with access to nutrients
  • transports CO2, O2, hormones, nutrients, nitrogenous wastes
51
Q

describe how connective tissue functions in protection

A
  • cells of the immune system
  • bone tissue
  • fibrous connective tissue
52
Q

what are the 3 types of muscle tissue

A
  • skeletal
  • smooth
  • cardiac
53
Q

describe the difference between the muscular system as a technical term and the muscular system as it is used in practice

A
  • technically the muscular system contains all muscle cells in the body; all 3 types
  • in practice the muscular system is used to describe the system of 650 skeletal muscles only
54
Q

how many skeletal muscles are there

A

650

55
Q

describe the structure of skeletal muscle cells

A
  • can be very large and thick
  • cylindrical
  • multinucleated
  • striated
56
Q

how long can skeletal muscle cells be

A

as long as the muscle they are apart of

57
Q

can you see skeletal muscle cells with the naked eye

A

no, but almost

58
Q

define striations

A
  • stripes perpendicular to the cell
  • exist because of arrangement of contractile machinery in the cell
59
Q

describe the structure of smooth muscle cells

A
  • fusiform/spindle shaped
  • mononucleated
  • not striated
  • embedded across many organ systems
60
Q

why can it be difficult to see smooth muscle cells under a microscope

A

cells do not lie perfectly flat on one another

61
Q

why do smooth muscle cells not have striations

A

they have a different arrangement of their contractile machinery that is not visible in the form of striations

62
Q

where is smooth muscle found

A
  • walls of hollow organs (bladder, blood vessels, uterus, airways to lungs, digestive organs)
  • NOT in the heart
63
Q

describe the structure of cardiac muscle cells

A
  • mostly mononucleated
  • rectangular-shaped cells
  • only found in the heart
  • striations
  • gap junctions between cells creating intercalated discs
64
Q

what is the major tissue of the heart that accounts for most of its mass

A

cardiac muscle tissue

65
Q

describe the function of skeletal muscle

A
  • large and powerful
  • always can be controlled consciously
  • only activated by the nervous system
  • moves the skeleton
  • amitotic (they do not divide)
66
Q

how are skeletal muscles controlled

A
  • only by nervous system
  • axon of a neuron must stimulate the muscle cell directly
  • voluntary control
67
Q

describe the function of smooth muscle

A
  • not large, but have high endurance (can stay contracted longer)
  • never controlled consciously
  • regulates the size of the lumen of hollow organs (except the heart)
  • can be controlled by nervous system, endocrine system, etc.
68
Q

how are smooth muscles controlled

A
  • controlled by nervous system impulses or endocrine system hormones
  • also contract instinctively when stretched
  • involuntary control
69
Q

describe the function of cardiac muscle

A
  • not large, but spectacular endurance
  • never controlled consciously
  • contraction stimulated by pacemaker within the heart (can be influenced by nervous system
70
Q

how can the nervous system influence the contractions of cardiac muscle

A
  • force and frequency
  • can only be influenced within a certain range (you can stop or start your heart)
71
Q

what cells can gap junctions exist in

A
  • can be in all cell types
  • prominent in cardiac muscle
72
Q

what creates the appearance of intercalated discs in cardiac muscle

A

gap junctions between cardiac muscle cells

73
Q

why are gap junctions important in cardiac muscle

A
  • electrical potential
  • allow current to flow through cells effectively and efficiently
  • allows heart to contract at the same time
74
Q

does the heart rely on nerves to beat

A

no, makes own impulse to beat within the pacemaker of the heart

75
Q

define current

A

any charged particle that moves from one location to another in organized movement

76
Q

describe the structure of gap junctions

A

protein channels connecting adjacent cells’ cytoplasm

77
Q

what are the two main cell types in nervous tissue

A
  • neurons
  • glial cells
78
Q

describe the structure of neurons

A
  • cell body with nucleus
  • axon: projection from the cell body to propagate (send) signals
  • dendrites: projections from the cell body to accept signals
79
Q

describe the function of neurons

A
  • sensory reception to gain information about the environment
  • integration/decision making/command and control
80
Q

how many neurons are in the brain and how does this compare to the number of glial cells

A
  • 100 billion neurons
  • 50-100x glial cells
81
Q

describe the structure of glial cells

A
  • diverse, as they have diverse functions of support
  • 4-5 types
82
Q

describe the function of glial cells

A
  • support neuron function
  • holding neurons in place
  • guiding neurons to the correct place during development
  • keeping neurons connected to each other
  • regulating levels of Na+ and K+ in interstitial fluid
83
Q

are glial cells essential

A
  • yes
  • especially in the CNS