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
briefly describe nervous tissue
- major tissue type of the nervous system - cells convey electrochemical signals for sensing, decision making, and control or support those that do
26
examples of senses of the nervous system
- the 5 senses: sight, smell, touch, taste, vision - pain - temperature - pressure - vibration - etc.
27
describe the structure of epithelial tissue
- cells take up max volume, minimal extracellular space - has basal and apical surface - desmosomes connect adjacent cells
28
define basal surface and apical surface
- basal: attached to thin fibrous basement membrane - apical: faces the void
29
describe desmosomes
- 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
30
describe hemidesmosomes
- attaches cell to basement membrane - half of a desmosome on the bottom of the cell
31
why is it important for epithelial cells to have desmosome connections
- 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
32
what are the 5 functions of epithelial tissue
- 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)
33
describe how epithelial tissue provides mechanical protection
50+ layers of keratinized cells in the epidermis protect underlying structures from abrasion/friction
34
describe how epithelial tissue is a barrier for chemicals and small particles
- 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
describe how epithelial tissue functions as passage for certain molecules
- 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
why are alveoli important
- 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
describe the structure of connective tissue
- cells inhabit a relatively small volume - much of the volume found between cells in the extracellular matrix
38
what does the extracellular matrix of connective tissue include
- collagen fibers - reticular fibers - elastin fibers - ground substance - interstitial fluid
39
what is the ground substance of the extracellular matrix of connective tissue composed of
proteins and carbohydrates that are not fibrous
40
what are the 6 functions of connective tissue
- binding - support and movement - storage - padding and insulation - transport - protection
41
describe how connective tissue functions by binding
connective tissue binds the tissues within an organ, organs to one another, and organs to the body wall
42
describe how connective tissue functions in support and movement
- essential for the musculoskeletal system to execute core functions - tendons and ligaments are made of dense regular connective tissue
43
what type of tissue are tendons and ligaments made of
dense regular connective tissue
44
define tendons and ligaments
- tendons: connect muscle to bone - ligaments: connect bone to bone
45
are bones and muscles organs
yes
46
how many bones are in the skeletal system
206
47
describe how connective tissue functions in storage
- bone tissue stores calcium and phosphate - adipose tissue stores fat
48
describe the purpose of calcium and phosphate in bones
- used to make bones rigid and hard - stored in the bones, can be released from the bone when needed elsewhere in the body
49
describe how connective tissue functions in padding and insulation
- adipose tissue - subcutaneous fat insulates the whole body
50
describe how connective tissue functions in transport
- blood is a connective tissue, connects all tissues with access to nutrients - transports CO2, O2, hormones, nutrients, nitrogenous wastes
51
describe how connective tissue functions in protection
- cells of the immune system - bone tissue - fibrous connective tissue
52
what are the 3 types of muscle tissue
- skeletal - smooth - cardiac
53
describe the difference between the muscular system as a technical term and the muscular system as it is used in practice
- 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
how many skeletal muscles are there
650
55
describe the structure of skeletal muscle cells
- can be very large and thick - cylindrical - multinucleated - striated
56
how long can skeletal muscle cells be
as long as the muscle they are apart of
57
can you see skeletal muscle cells with the naked eye
no, but almost
58
define striations
- stripes perpendicular to the cell - exist because of arrangement of contractile machinery in the cell
59
describe the structure of smooth muscle cells
- fusiform/spindle shaped - mononucleated - not striated - embedded across many organ systems
60
why can it be difficult to see smooth muscle cells under a microscope
cells do not lie perfectly flat on one another
61
why do smooth muscle cells not have striations
they have a different arrangement of their contractile machinery that is not visible in the form of striations
62
where is smooth muscle found
- walls of hollow organs (bladder, blood vessels, uterus, airways to lungs, digestive organs) - NOT in the heart
63
describe the structure of cardiac muscle cells
- mostly mononucleated - rectangular-shaped cells - only found in the heart - striations - gap junctions between cells creating intercalated discs
64
what is the major tissue of the heart that accounts for most of its mass
cardiac muscle tissue
65
describe the function of skeletal muscle
- large and powerful - always can be controlled consciously - only activated by the nervous system - moves the skeleton - amitotic (they do not divide)
66
how are skeletal muscles controlled
- only by nervous system - axon of a neuron must stimulate the muscle cell directly - voluntary control
67
describe the function of smooth muscle
- 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
how are smooth muscles controlled
- controlled by nervous system impulses or endocrine system hormones - also contract instinctively when stretched - involuntary control
69
describe the function of cardiac muscle
- not large, but spectacular endurance - never controlled consciously - contraction stimulated by pacemaker within the heart (can be influenced by nervous system
70
how can the nervous system influence the contractions of cardiac muscle
- force and frequency - can only be influenced within a certain range (you can stop or start your heart)
71
what cells can gap junctions exist in
- can be in all cell types - prominent in cardiac muscle
72
what creates the appearance of intercalated discs in cardiac muscle
gap junctions between cardiac muscle cells
73
why are gap junctions important in cardiac muscle
- electrical potential - allow current to flow through cells effectively and efficiently - allows heart to contract at the same time
74
does the heart rely on nerves to beat
no, makes own impulse to beat within the pacemaker of the heart
75
define current
any charged particle that moves from one location to another in organized movement
76
describe the structure of gap junctions
protein channels connecting adjacent cells' cytoplasm
77
what are the two main cell types in nervous tissue
- neurons - glial cells
78
describe the structure of neurons
- cell body with nucleus - axon: projection from the cell body to propagate (send) signals - dendrites: projections from the cell body to accept signals
79
describe the function of neurons
- sensory reception to gain information about the environment - integration/decision making/command and control
80
how many neurons are in the brain and how does this compare to the number of glial cells
- 100 billion neurons - 50-100x glial cells
81
describe the structure of glial cells
- diverse, as they have diverse functions of support - 4-5 types
82
describe the function of glial cells
- 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
are glial cells essential
- yes - especially in the CNS