A&P 1: Block 2 Flashcards

1
Q

Accessory structures of the skin

A
hair
nails
glands
muscles
nerves
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2
Q

Where does the hypodermis layer fall into the layers of skin?

A

Sub-Q layer consisting of areolar and adipose tissue

Not a part of the skin

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3
Q

7 specific functions of the skin

A
Thermoregulation
Protection
Sensation
Excretion
Synth of Vitamin D
Blood reservoir
Absorption
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4
Q

Epidermis is composed of what type of epithelium?

A

Keratinized stratified squamous epithelium

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5
Q

What are the 4 types of cells within the epidermis?

A

Keratinocytes
Melanocytes
Langerhans
Merkel

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6
Q

90% of the epidermal cells are ____

A

keratinocytes

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7
Q

How/when are keratinocytes formed?

A

When new cells from mitosis fill with keratin

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8
Q

Major functions of keratin

A

Tough, fibrous protein that is
waterproof
protects (heat, microbes, chemicals)
UV protection

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9
Q

What part of the cell makes melanin?

A

Organelle melanosome within melanocytes

Melanin is brown-black pigment that contributes to skin color and absorbs UV light

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10
Q

After melanin is made by melanocytes, where is it transferred to? How does it get transferred?

A

Melanocyte projections extend between keratinocytes and pass melanin granules to them

Melanin granules cluster over nucleus on skin surface side, shields DNA from UV light

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11
Q

What is melanin synthesized from?

A

AA tyrosine w/ tyrosinase enzyme

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12
Q

Function of Langerhans cells?

What type of cell are they?

A

Immune response to microbes that invade the skin

Immune, dendritic

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13
Q

Where are Merkel cells found?

What is their function?

A

Deepest layer of epidermis (Stratum Basale)

Contact w/ tactile discs (Merkel discs), a type of sensory neuron

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14
Q

What two structures make up the sensation of touch?

A

Merkel cells

tactile discs

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15
Q

What are the layers of skin

A
Corneum
Lucidum
Granulosum
Spinosum
Basale

Lucidum- only present on surface areas of a lot of friction (finger tips, soles)

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16
Q

Characteristics of the Stratum Basale

A

Deepest layer of epidermis

Mostly keratinocytes, few melanocytes and Merkel cells

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17
Q

What are the intermediate filaments of keratinocytes and where is it found?

A

Tonofilaments
Intermediate filament of keratinocytes in the Stratum Basale
Contains pre-cursor protein for keratin synthesis

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18
Q

Characteristics of Stratum Spinosum

A

8-10 layers of keratinocytes, few Langerhans
Cells still alive at this layer, some are dividing
Older cells start to flatten here

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19
Q

Characteristics of Stratum Granulosum

A

3-5 layers of flattened keratinocytes
Transition marker for deeper living/superficial dead cells
Filled w/ keratin granules
Waterproofing lipids from lamellar granules are here

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20
Q

Characteristics of Stratum Lucidum

A

Only on fingertips, soles, palms

3 layers of flat, dead keratinocytes filled with keratin

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21
Q

Characteristics of Stratum Corneum

A

Most superficial
25-30 layers of flat, dead cells
Cell interior mostly keratin
Lipids from lamellar granules form waterproof layer here

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22
Q

What type of tissues make up the dermis

A

Irregular CT of collagen and elastic CTs

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23
Q

What structures are found in the dermis

A
vessels
nerves
glands (oil and sweat)
Hair follicles
arrectores pilorum
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24
Q

What are the two regions of the dermis?

A

Papillary- superficial

Reticular- deeper

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25
Q

Characteristics of the Papillary region of the Dermis

A

Just deep to stratum basale

Increases surface area for diffusion, better adhesion to epidermis

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26
Q

What receptors are present in the Papillary region of the Dermis

A

Touch corpuscles- Meissner- touch/light touch

Free nerve endings- no structural specialization- warm, cold, pain, tickle

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27
Q

Characteristics of the Reticular Region of the Dermis

A

Dense irregular CT w/ collagen and elastic
Gives skin it’s strength and elasticity

Spaces between fibers filled with adipose, follicles, nerves, oil and sweat glands

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28
Q

What layer of the skin provides the skin strength, extensibility and elasticity?

A

Reticular region

Collagen and elastic fibers

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29
Q

Subcutaneous layer is made of what tissues?

A

Areolar and adipose

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30
Q

What structures are found in the subcutaneous layer?

A

Fat
Fibers attaching dermis to deeper tissues
Larger vessels
Sensory receptors: Pacinian/lamellated corpuscles- pressure

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31
Q

Epidermal ridges aka

A

fingerprints

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32
Q

When do epidermal ridges form in development/

A

3 and 4th month of fetal development
Contours of underlying papillary region

Forms lines, loops and whorls

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33
Q

Where do sweat glands open to on fingertips?

A

Epidermal ridges

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34
Q

Skin color is a combination of what things?

Which ones are genetically determine?

A

melanin
carotene
hemoglobin

Amount/expression of melanin and carotene- genetically determined

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35
Q

What does melanin provide to skin?

What does increased sun exposure do to these cells?

A

Amount causes skin color

Increased exposure= increased enzymatic activity of malanosomes, increased melanin production

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36
Q

What does Carotene provide to skin?

A

yellow-orange pigment

Pre-cursor for Vitamin A

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37
Q

What does Hemoglobin provide to skin color?

A

O2 carrying pigment in RBCs
When Melanin or Carotene are low, epidermis appears translucent
Causes skin to appear pink

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38
Q

What are the parts of the skin’s hair shaft and root?

A

Medulla
Cortex
Cuticle

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39
Q

What are skin hairs composed of?

A

Dead, keratinized cells bonded by proteins

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40
Q

How do skin hairs grow?

A

Cell division at base of follicle via mitosis in the hair matrix

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41
Q

What is the canal called that skin hairs grow through?

A

Pilary canal

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42
Q

What is the hair bulb made of?

A

Germinal layer of cells called matrix

Site of cell division that produces the hair

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43
Q

What layer does the hair bulb come from?

A

Stratum basale

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44
Q

What are the ancillary structures of hair?

A

Sebaceous gland
Smooth muscles
Root plexus

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45
Q

What type of cells surround the root hair plexus?

A

Dendrites
Nerve endings

Generates nerve impulses if hair shaft is moved
Shaft acts like a fulcrum

Sensitive to touch and movement

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46
Q

What are the 3 parts of a nail?

A

Body- visible (lunula- white part of proximal nail)
Free edge
Root- epithelium deep is the nail matrix, mitotic division= growth

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47
Q

What are nails made of?

A

Keratinized epidermal cells

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48
Q

When nails grow, new cells push old ones forward along what basale?

A

Stratum

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49
Q

3 functions of sebum?

A

Prevents drying out
Prevents evaporation
Inhibits bacterial growth

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50
Q

What are the two types of sweat glands?

A

Eccrine- (merocrine) found on most of skin, thermoregulation

Apocrine- hair that develops at puberty (axilla, groin, beard)

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51
Q

Define psoriasis

Where is it commonly found?

A

keratinocyte division and movement more rapidly than stratum basale/corneum and shed prematurely

Knees, elbows, scalp

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52
Q

Virtually all skin cancers are attributed to excessive ___

A

sun

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53
Q

What are the 3 common forms of skin cancer?

A

Basal cell carcinomas- most common
Squamous carcinoma
Malignant melanomas (least common, most life-threatening)

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54
Q

Define albinism

A

inability to produce melanin

melanocytes unable to synthesize tyrosinase

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55
Q

Define vitiligo

A

Partial/complete loss of melanocytes from patches of skin (irregular white spots)

May be autoimmune

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56
Q

Under lying causes of erythema

A

redness of skin

injury
heat
infection
inflammation
allergies
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57
Q

Define striae

A

stretch marks

scars from dermis tearing

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58
Q

Define alopecia

What are its causes

A
lack of hair (partial or complete)
aging
endocrine disorder
chemotherapy
skin disease
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59
Q

Define contact dermatitis

A

inflammation of skin (redness, itching, swelling)

Caused by exposure of skin to chemicals= allergic reaction

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60
Q

What are the two types of wound healing

A

Epidermal- superficial, only epidermis involved

Deep wound- injury extends to dermis and subcutaneous layer (loss of some function and scar tissue)

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61
Q

What are the 4 overall steps of Deep Wound Healing?

A

Inflammatory
Migratory
Proliferative
Maturation

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62
Q

Characteristics of 1st degree burn

A

Only epidermis
Skin functions remain intact
3-6 day heal time
Sunburn

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63
Q

Characteristics of 2nd degree burn

A

Partial damage to epidermis and dermis
Some skin function lost (blisters)
3-4 wks heal time w/ scarring possibility

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64
Q

Characteristics of 3rd degree burn

A

Epidermis and dermis involvement
Skin function lost
AKA full thickness

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65
Q

Rule of 9s

A

Only for 2nd and 3rd degree burns on adults

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66
Q

Define abrasion

A

skin has been scraped away

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67
Q

Define Athletes foot

A

superficial fungal infection of skin on foot

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68
Q

Define blister

A

serous fluid with epidermis or between epidermis and dermis

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69
Q

Define callus

A

area of hardened/thickened skin

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70
Q

Define eczema

A

inflammation of skin characterized by patches of blister/dry/itch skin

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71
Q

Define wart

A

mass of uncontrolled growth of epithelial cells caused by papillomavrius

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72
Q

Define hirsutism

A

condition of excessive body hair

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73
Q

Define laguno

A

fine,non-pigmented hairs that cover body of fetus

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74
Q

Define Terminal Hairs

A

Secondary characteristic
Coarse, heavily pigmented
Head, eyebrows, eyelashes

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75
Q

Define Vellus hairs

A

fine/pale body hairs that develop during childhood

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76
Q

What does cartilage consist of?

A

Collage (strength) and elastic fibers embedded in chondroitin sulfate (resilience)

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77
Q

What are mature cartilage cells called? What space do they occupy?

A

Chondrocytes= mature
Derived from chondroblasts
Reside in lacunae (little lakes)

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78
Q

Most cartilage is covered in irregular CT called ____.

What developmental shift occurs to this tissue?

A

perichondrium

Becomes vascularized, becomes periosteum

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79
Q

Cartilage has no nerves except for where?

A

Perichondrium

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80
Q

Why does perichondrium cartilage heal slowly?

A

lack of intrinsic blood supply and confinement of chondrocytes to lacunae

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81
Q

What are the 3 types of cartilage

A

Hyaline- most abundant
Fibrinocartilage
Elastic

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82
Q

Where is Hyaline cartilage located?

A

Most abundant
End of long bones
Ribs, nose, trachea, bronchi and larynx
Provides smooth surface for movement to occur

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83
Q

Characteristics of fibrinocartilage and where is it located

A

thick bundles of collagen (very tough/strong)

Found as disc shaped segment between bones

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84
Q

Characteristics and location of elastic cartilage

A

Chondrocytes located in threadlike network of elastic fibers

External ear and epiglottis

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85
Q

Different functions of red and yellow bone marrow

A

Red- RBC formation

Yellow- triglyceride storage (adipose connective tissue)

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86
Q

Define diaphysis
Define epiphyses
Define metaphyses

A

Di- shaft, body of bone
Epi- distal/proximal portion of bone
Meta- connects Di and Epi

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87
Q

Where is the epiphyseal plate located?

A

at metaphyses of growth plate

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88
Q

Define articular cartilage

A

hyaline cartilage covering epiphyses

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89
Q

Define periosteum

A

dense irregular CT that covers bone, EXCEPT articular cartilage

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90
Q

Define endosteum

A

membrane lining marrow cavity

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91
Q

Histology break down of bone matrix

don’t know %s

A

25% water
25% collagen
50% hydroxyapatite- (calcium phosphate, calcium carbonate) for hardness/compression strength

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92
Q

What are the 4 cells found in bones

All derive from mesenchyme*

A

mesenchyme- 1st
Osteogenic- stem cells differentiate->osteoblasts

Osteoblasts- secrete bone matrix and become osteocytes

Osteocytes- mature bone cell, regulate bone matrix composition

Osteoclasts- release enzymes for digesting/remodeling bone

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93
Q

Regions of bones can by subcategorized into what 2?

A

Compact- cortical

Spongy- cancellous, trabecular

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94
Q

Compact bones contain units called?

A

Osteons- Harversian systems formed from concentric lamellae (rings of calcified matrix)

Interstitial lamellae- between osteons, left over fragments of older osteons

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95
Q

Where are the outer/inner circumferential lamelle located?

A

Outer- encircles bone beneath periosteum

Inner- encircles medullary cavity

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96
Q

Define lacunae

What connects these?

A

small spaces between lamellae which house the osteocytes

Connected by Canaliculi- channels w/ ECF

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97
Q

Where are blood and lymph vessels found within bone tissue?

A

Central canal

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98
Q

Define perforating (Volkmann’s) canals

A

allows transit of blood/lymph vessels to the outer cortex of bone

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99
Q

Spongy bone lacks ____

What replaces them?

A

Osteons

Lamellae arranged in lattice of thin columns called Trabeculae

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100
Q

Function of Trabeculae?

A

Spongy bones- support and protect red marrow, helps bones resist stress w/out breaking

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101
Q

Define hematopoiesis and where does it take place

A

blood cell production

Spongy bone

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102
Q

Within each trabecula of spongy bones there are what sub-structures?

A

Lacunae- osteocyte containing area for bone nourishment via blood circulating through trabeculae

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103
Q

What is the name of the process of forming new bones?

A

Ossification or,

Osteogenesis

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104
Q

What are the 4 situations that bone formation occurs?

A

Embryo development
Adulthood
Remodeling
Fx repair

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105
Q

What are the two different methods of osteogenesis?

A

Intra-Membrane ossification- (simpler) spongy bone production (can be remodeled into compact)

Endochondral ossification- process where cartilage is replaced by bone (forms both spongy and compact)

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106
Q

Give examples of Intra-membranous ossification process

A

Skull, mandible, clavicle
mesenchyme->develop w/in membrane->NO cartilage stage
Many ossification centers

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107
Q

Give examples of Endochondral ossification process

A

Most bones, especially long bones

Replacement of cartilage by bone
One primary and 2 secondary centers of growth

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108
Q

What are the two processes of bone remodeling?

A

resorption

deposition

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109
Q

Define acromegaly

A

bones are too thick and heavy

Too much new tissue

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110
Q

Bones can become too soft such as what 2 diseases?

A

Rickets

Osteomalacia

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111
Q

Steps/process of bone Fx healing

A

1: 6-8hrs after injury, formation of Fx hematoma from vessels breaking in periosteum and osteons
2/3: formation of callus (wks-6mon), phagocytes remove debris, fibroblasts deposit collagen to form fibrocartilaginous callus
Osteoblasts form bony callus of spongy bone
4: remodeling (several months) spongy replaced by compact, Fx line disappears, evidence remains

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112
Q

Function of Vitamin A in growth/remodeling

A

stimulates osteoblasts activity

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113
Q

Function of Vitamin C in growth/remodeling

A

Collagen synthesis

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114
Q

Function of Vitamin D in growth/remodeling

A

Ca absorption in GI tract

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115
Q

Function of Vitamin K/B12 in growth/remodeling

A

Bone protein synthesis

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116
Q

Importance of Ca homeostasis and where is it stored

A

Synaptic transmission, muscle contraction, blood clotting

99% stored in bones

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117
Q

Function of parathyroid hormone and bone structure

A

PH promotes resorption of bone matrix
prevents loss of Ca in urine
Promotes Vitamin D formation

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118
Q

Name of Vitamin D and it’s main function

A

Calcitriol- promotes Ca absorption in intestines

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119
Q

What is the production site and function of Calcithonin

A

Produced in parafollicular cells of thyroid gland

Lowers blood Ca levels by inhibiting reabsorption

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120
Q

What are the two main ways Ca blood can be increased?

A

Release of Ca from bone matrix

Retention of Ca in kidneys

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121
Q

Definition of joints

A

point of contact between two bones, bone and cartilage, or between bone and tooth

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122
Q

Define suture joint

A

thin layer of fibrous CT

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123
Q

Define syndesmoses

A

more space than suture, more fibrous CT

Epiphyseal plate

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124
Q

Define gomphoses

A

teeth in sockets of upper/lower jaw

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125
Q

What are the components of cartilaginous joints?

A

Fibrocartilage/hyaline cartilage
No synovial cavity
Little/no movement

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126
Q

What are the two types of Cartilaginous joints

A

synchondroses- primary cartilaginous join; hyaline cartilage connecting bones (may ossify w/ age)

symphyses- secondary cartilaginous; fibrocartilage

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127
Q

Characteristics of synovial joints

A

most moveable
Articular capsule- dense ir/regular
Synovial mem- secretes fluid
May contain articular discs (menisci)

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128
Q

List the 4 characteristics of Muscular tissue

A

irritable
contractable
extensible
elastic

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129
Q

What is a single muscle fiber called?

What is a bundle of muscle fibers called?

A

myofiber

Fascicle

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130
Q

Define myofibril

A

organelle in a muscle fiber composed of filaments

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131
Q

Define endomysium
Perimysium
Epimysium

What do these 3 join together to form?

A

Endo- CT surrounding a fiber
Peri- surrounds fascicle
Epi- surrounds entire muscle

Tendons

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132
Q

What does eccentric mean

A

Multi-nucleated (skeletal muscles)

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133
Q

Define aponeurosis

A

*fill in
related to CT and tendons
Slide 7

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134
Q

What comprises a motor unit

A

Somatic motor neuron supplying a group of muscle fibers (1:1)

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135
Q

What is a neuromuscular junction

A

site where neuron contacts the muscle fiber

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136
Q

Why are skeletal muscles multi-nucleated?

A

During embryonic development, myoblasts fuse to form one skeletal muscle fiber
Prevents muscle fibers from being able to undergo mitosis

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137
Q

What is the sarcolemma?

What is the sarcoplasma?

A

Lemma- plasma membrane of an individual muscle fiber

Plasma- cytoplasm of skeletal muscle fibers

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138
Q

Where are sarcoplasm “chocked full”

A

contractile proteins arranged into myofibrils

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139
Q

What is the T-tubule and what are their functions?

A

Transverse tubules
“cul-de-sacs from outside of fiber towards interior (invaginate from sarcolemma to interior)
Filled w/ interstitial fluid
Propagation of muscle APs

140
Q

Define sarcoplasmic reticulum

A

Smooth ER of muscle fiber

Stores Ca ions and releases them during muscle stimulation

141
Q

What is the unique/special protein located in the sarcoplasmic reticulum?

A

Calsequestrin- Ca binding protein in sarcoplasmic reticulum which enables muscle relaxation to have a Ca concentration 10,000x higher than cytosol

142
Q

Define Terminal Cisterns

What do the form?

A

dilated region that flank T-tubules

2 cisterns flanking 1 T-tubule= Triad

143
Q

What is the basic functional unit of a skeletal muscle?

A

sarcomere: arrangement of filaments between two Z discs

144
Q

Myofibrils are made of smaller structures called?
How many types?
What is their ratio?

A

Filaments
Thin: actin (contractile) Troponin (regulatory) Tropomyosin (regulatory)
Thick: myosin (contractile)

2 thin:1 thick

145
Q

Filaments inside myofibrils are arranged compartments called ____?

A

sarcomeres, the basic unit of a myofibril

Connected at/by Z disc

146
Q

Long chains of sarcomeres are called a ____?

A

myofibril

147
Q

What structure make up the striation of muscles?

A

Thick and thin filaments seen in single myofibrils and whole muscle fibers

148
Q

Overlapping of sarcomeres causes zones and bands, what are they?

A

A band
I band

Z line
M line

H zone

149
Q

Define Z disc

A

where adjacent sarcomeres abut*

Center of an I band

150
Q

Define A band

A

darker zone

gives length of thick filaments and varying overlap of thin filaments

151
Q

Define I band

A

only thin filaments

consist of parts of 2 adjacent sarcomeres

152
Q

Define H zone

A

center of A band

only thick filaments

153
Q

Define M line

A

midline of a sarcomere

154
Q

Thick filament is composed of ____molecules
What do their tails form?
What doe their heads form?

A

myosin
Tails form thick filaments
Heads (cross bridges): bind/hydrolyze ATP and the products (ADP and phosphate), change shape (to/away from M line) and bind reversibly w/ actin

155
Q

How do proteins link together in thin/thick filaments?

A

Thin- acting proteins, peal strands

Thick- myosin proteins, golf clubs bound together

156
Q

What movement in the fine structure allows contraction to begin?
What triggers this?

A

movement of troponin-tropomyosin complex

Triggered by Ca binding to tropnin

157
Q

Contractile proteins
Regulatory proteins
Structural proteins

A

Contract- myosin, actin
Reg- troponin, tropomyosin
Structure- titin, myomesin, dystrophin, sarcolemmal proteins

158
Q

Define titin filament and its function

A

molecule spans half a sarcomere, Z disc from M line

Attaches thick filament to Z disc and M lines

helps sarcomere return to resting strength

159
Q

Function of dystrophin

A

links thin filaments of sarcomere to integral membrane proteins in sarcolemma

transmits the tensive forces of sarcomere

160
Q

Define Duchenne Muscular Dystrophy

A

Most common
Gene coding for dystropphin is mutated, results in little/no dystrophin in sarcolemma. Sarcolemma tears easily during contraction leading to rupture and tissue death

161
Q

Where is the AP generated in a muscle cell?

How does it travel into the muscle fiber?

A

Neuromuscular junction

Along entire sarcolemma and down T-tubules to fiber interior

162
Q

Function of neuromuscular junction

A

synapse between somatic motor neuron and skeletal muscle fiber

163
Q

How is AP carries across a synaptic cleft?

A

synaptic end close to axon terminal s/ synaptic vesicle filled w/ ACh
ACh carries impulse across

164
Q

Where is the motor end plate and what is it comprised of?

A

part of sarcolemma opposite of synaptic bulb

comprised of muscle fiber part of NMJ

165
Q

Define junctional folds

A

ACh receptors, transmembrane proteins in motor end plate residing in deep grooves

166
Q

What happens after ACh binds?

A

2 ACh opens ion channel in CAh receptor, allowing Na to flow across membrane

Influx of Ca=more pos charge, AP triggered

167
Q

Why is bacterium Clostridium botulinum bad

A

produces toxin that blocks exocytosis of synaptic vesicle in NMJ

muscular paralysis since ACh is not released, contraction can’t occur

168
Q

Explain sliding filament machanism

A

Exposed myosin binding site on actin (thin filaments), w/ Ca and ATP, thick and thin slide on each other, sarcomere shortened

169
Q

What are the 4 steps of the Sliding Filament Mechansim

A

1- ATP hydrolysis: myosin heads hydrolyze ATP
2- Attachment: myosin head binds w/ actin, forming cross bridge
3- Power stroke: cross bridge rotate towards sarcomere center
4- Detachment: myosin heads bind ATP, cross bridge detaches from actin (detachment occurs ONLY when ATP bind to myosin heads)

170
Q

How do zones/band length changes during contraction?

A

H and I: decrease
A: no change, constant
Sarcomere length: decreases
Thick and thin: no change in length

171
Q

Explain contraction process during rigor mortis

A

3-4 hrs after death
membranes leak Ca, binds w/ Troponin-Tropomyosin, cross bridges attach and complete 1 power stroke
No more ATP production= cross bridges can’t detach from actin, produces rigidity
24hrs after death, proteolytic enzymes from lysosomes digest crossbridges

172
Q

Define hypertrophy

A

increase in muscle fiber diameter
inc organelle number
more myofibrils=more forceful contractions

173
Q

Define hyperplasia

A

increase in tissue/organ size DUE TO increased cell number

174
Q

What type of muscle growth occurs after birth

A

hypertrophy of existing muscles

no hyperplasia, no mitosis

175
Q

What are the 2 primary hormones that stimulate skeletal muscles?

A

HGH

testosterone

176
Q

Define myoglobin

A

red colored protein found only in muscles
similar to HgB (structure, chemistry, function)
Binds O2 and releases for mitochondria during high aerobic respiration

177
Q

What is the use of ATP for muscle contraction?

A

Na/K pumps- active transport, AP production
Ca ion pumping- active transport, contraction termination
Energizes myosin head in prep for power stroke

178
Q

ATP production is via what 3 things?

A

creatine phosphate
glycolysis
aerobic respiration

179
Q

What is the sequence of ATP sources during max sustained contraction?

A

ATP
creatine phosphate
glycolysis
aerobic cellular resp.

180
Q

What are the usual sources of creatine in the body?

A

Synth in liver, kidneys, pancreas

Derived from milk, red meat and fish

2g/day is needed
excess may cause dehydration and kidney dysfunction

181
Q

The force that a single fiber can produce is primarily dependent on _____?
What is it’s frequency?

A

Rate at which it is stimulated (nerve impulses arriving at the neuromuscular junction)
Frequency- number of impulses per unit time (typically, per second)

182
Q

Define twitch

A

brief contraction of all muscle fibers in a motor unit

aka twitch contraction

183
Q

Define use/function of a myograph

What is it an example of

A

measures force generated by direct stimulation of either motor neuron/muscle fibers
Transducer- converts one form of energy into another

184
Q

What are the periods of a myograph associated with?

A

Ca++ movements, stretching and elasticity

185
Q

In reference to myographs, define refractory period

When does it start and end?

A

period of time after first stimulus when response to a second stimulus is not possible
Start: stimulation
Ends: early part of contraction period, duration varies

186
Q

Define myograph latent period
Contraction period
Relaxation period

A

Latent: muscle AP travels over sarcolemma, Ca is released from sarcoplasmic reticulum

Contraction: Ca bind to tropinin, cross bridges form, peak tension develops in muscle fiber

Relaxation: Ca+ actively transported back to sarcoplasmic reticulum, myosin binding sites covered by tropomyosin, myosin heads detach from actin, tension in muscle fibers decrease

187
Q

Define summation

A

second stimulus occurs after refractory period but before muscle fiber is relaxed, causes second contraction to be stronger than first contraction
More Ca+ is released from sarcoplasmic reticulum

188
Q

What accounts for the initial/apparent gain of strength after starting an exercise routine/program?

A

more efficient motor recruitment

not necessarily increased contractile force capability

189
Q

Define motor unit recruitment

A

number of active motor units is increased according to need

More neurons activated in spinal cord, more motor units will be stimulated, more muscle tension will be produced

190
Q

What motor units are recruited first/last during contraction?

A
First= smallest/weakest
Last= larger, stronger
191
Q

Cardiac muscle contraction lasts _-_x longer than a skeletal muscle contraction
How is this accomplished?

A

Cardiac= 10-15x

O2 delivery by coronary circulation to generate ATP through aerobic respiration

192
Q

Cardiac muscle exhibit what unique capability

How do they maintain this?

A

autorhythmicity
75/min
Altered by NS and endocrine system
Larger/numerous mitochondria

193
Q

How does smooth autorhythmic muscle generate ATP?

A

anaerobic respiration (glycolysis)

194
Q

What types of filaments are in smooth muscles?

A

Thick, thin and intermediate
Intermediate attach to dense bodies (functionally similar to Z discs) found in sarcoplasma and sarcolemma

Contraction of thick and thin generates tension on intermediates, pulls dense bodies and causes shortening

195
Q

What are the two types of smooth muscle?

A

Single unit smooth- AKA visceral smooth
Multiunit smooth

Distinguished by number of fibers that comprise a motor unit

196
Q

How are the two types of smooth muscle distinguished?

A

Visceral- smooth muscle fibers connect to one another by gap junctions and contract as a single unit

Multiunit- lack gap junctions and contract independently

197
Q

Exercise induced muscle damage is evident in what phycical/chemical parts of muscle/what structures?

A

Physical:
Torn sarcolemmas
Damaged myofibirls
Disrupted Z discs

Chemical:
increased blood levels of myoglobin and creatine kinase

198
Q

Define DOMS

A

Delayed onset muscle soreness

12-48hrs later, microscopic muscle damage is major factor

199
Q

Define muscle fatigue

What does it result from?

A

inability of muscle to maintain force of contraction after prolonged activity

Changes within muscle fibers: inadequate Ca ion release, depleted creatine phosphate, low O2/glycogen, increased lactic acid and ADP, failure of action potential to release acetylcholine

200
Q

What condition precedes muscle fatigue

A

Central fatigue- tiredness and sensation to cease activity

201
Q

Define muscle tone

A

Small tension/contraction in muscle caused by involuntary contractions of motor units

Established by neurons in brain and spinal cord

202
Q

Why is muscle tone important?

A

Posture, pressure on digestive organs, BP

203
Q

Define flaccid

A

state of limpness where muscle tone is lost

Caused by severed motor neurons in skeletal muscles

204
Q

Neuromuscular disease is a disease/damage to what 3 components of the motor unit?

A

Somatic motor neuron
Neuromuscular junctions
Muscle fibers

Neuromuscular disease encompasses problems at all 3 sites

205
Q

Define Myasthenia Gravis

A

Autoimmune disease
Causes chronic/progressive damage of neuromuscular junction by producing Abs that bind and block acetylcholine receptors, decreases number of functional receptor at motor end plates
Causes weakness/fatigue and eventual loss of muscle function

206
Q

Define spasm

A

sudden involuntary contraction of single muscle that is part of a large group of muscles

207
Q

Define cramp

A

painful spasmodic contraction

Caused by inadequate blood flow, overuse, dehydration, extended holding/flexion, low electrolytes

208
Q

Define tic

A

spasmodic twitch made involuntary by muscles that are ordinarily under voluntary control

209
Q

Define tremor

A

rhythmic, involuntary contraction that produces quivering/shaking

210
Q

Define fasciculation

A

brief involuntary twitch of an entire motor unit that is visible under the skin
occurs regularly and is not associated w/ movement of affected muscle

211
Q

Define fibrillation

A

Spontaneous contraction of single muscle fiber that isn’t visible under skin but is detectable by electromyography
May cause signaling for motor neuron destruction

212
Q

Define myopathy

A

Disease or disorder of skeletal muscle tissue

213
Q

Define muscle strain

A

Forceful stretching/tearing of muscle fibers

Quadriceps femoris frequently affected

214
Q

Define myalgia

A

pain in/associated w/ muscles

215
Q

Define myoma

A

tumor of muscle tissue

216
Q

Define myositis

A

inflammation of muscle tissue

217
Q

Define myotonia

A

slow relaxation/decreased ability to relax muscles after voluntary contraction
May be accompanied by increased muscular excitability and contractility

218
Q

Define Myomalacia

A

pathological softening of muscle tissue

219
Q

What is in the CNS?

What is in the Peripheral NS?

A
CNS= Brain and Spinal cord
PNS= cranial nerves (12 pairs)
spinal nerves (31 pairs)
Peripheral nerves (numerous)
220
Q

What components make up the entire nervous system?

A
Brain
Spinal cord
Spinal nerves
Ganglia
Enteric plexuses
Sensory receptors
221
Q

Define sensory nerves

A

Detect changes internally/externally
Carry sensory info from receptor to brain/spine
Afferent neurons

222
Q

Define integrative nerves

A

Analyze and store info, makes decisions

Most are interneurons- short neurons in brain, spine and ganglia

223
Q

Define motor nerve

A

Respond to decisions
Carry info from brain/spine to effectors (muscle/gland)
Efferent neurons

224
Q

Define somatic nerve

A

Sensation from body wall, limbs, head, special senses

Motor control of skeletal muscle

225
Q

Dfine autonomic nerve

A

Sensation from internal organs

Motor control of smooth and cardiac muscle and glands

226
Q

Define enteric nerve

A

Sensation of GI tract

Motor control of smooth muscles and glands of GI tract

227
Q

Difference between neuron and ganglion

A

Nerve: association/bundle of neuronal axons in PNS
Ganglion: group of neuronal cell bodies in PNS and associated tissues

228
Q

Define tract

A

association/bundle of neuron axons in CNS

229
Q

Define nucleus

A

bundle of unmyelinated nerve cells in CNS

230
Q

Define plexus

A

Nerve network in PNS

Can also apply to network of veins/lymph vessels

231
Q

Define neuron

A

Electrically excitable

Adapted to produce/transmit AP

232
Q

Define neuroglia

A

NS cells that support, nourish and protect neurons

More neuroglia than neurons

233
Q

What are the basic parts of the neuron

A

Cell body

Fibers- axon, dendrites

234
Q

What is the axoplasm

What is the axolemms

A

plasm- axon cytoplasm

lemma- axon plasmalemma

235
Q

What organelles do neurons have?

A
Nucleus
Cytoplasm
Lysosome
Golgi
Mitochondria

Nissi bodies- clusters of RER

236
Q

What are the special functional adaptations of neurons

A

Dendrites- little trees, receiving portion of neuron. Short, tapered, highly branched

Axon- propagates impulse to next neuron/muscle/nerve
Can reach up to 3ft long

Do not replace, no mitosis

237
Q

Define axon hillock

A

small hill

elevation in cell body that axon arises from

238
Q

Where does the AP originate from?

A

Trigger zone of neuron

Junction of hillock and initial segment

239
Q

What is the first part of the neuron called?

What happens if axon is cut?

A

initial segment

distal fragment dies

240
Q

What organelles do axons have?

What organelle is not found in axons?

A

Mitochondria
Microtubules
Neurofibirls

RER, no protein synth. Takes place in cell body

241
Q

Define telodendria

How do the terminate?

A

Axon terminals

Synaptic end bulbs
Varicosities- string of swollen bumps

242
Q

What are the 2 components of the neuron cytoskeleton?

A

Neurofibrils- intermediate filaments, provide shape/support to cell

Microtubules- tubulin, move material between cell body and axon

243
Q

Define slow axonal transport

A

one way only from cell body -> terminals

transports to growing/regenerating axons

244
Q

Define fast axonal transport

A

2 way transport
Microtubules are used as tracks/motors
Transports organelles and materials to form axolemma membranes, synaptic bulbs and vesicles

245
Q

Define structural classification

A

Based on number of axon/dendrite processes extending from cell body

246
Q

Define multipolar neuron

A

Several dendrites, only one axon
Located in brain and spinal cord
Composes vast majority of neurons in human body

247
Q

Define bipolar neuron

A

One dendrite, one axon
Convey special senses signals
Located in retina, inner ear and olfactory area of brain

248
Q

Define unipolar neuron

A

Pseudounipolar neuron
One process: from body -> central branch that functions as axon
Employed as sensory neurons that convey touch and stretch info from extremeties

249
Q

Define neuroglia

A

Non-excitable support cells
Smaller and more numerous than neurons
Compose half of CNS volume, will occupy space lost during injury/disease

250
Q

Which neuroglias are found/located in the CNS?

A

Astrocytes
Oligodendrocytes
Microglia
Ependymal cells

251
Q

Where are neuroglia located in the PNS?

A
Schwann cells (neurolemmocytes)
Satellite cells
252
Q

Function of astrocytes

A

Regulate ECF composition in CNS
Help form BBB
Absorb excess neurotransmitter
Influence neural synapse formation

253
Q

Function of oligodendrocyte

A

Myelinate axons in CNS

254
Q

Function of microglial cells

A

Phagocytes of CNS

255
Q

Function of ependymal cells

A

Line brain ventricles
Produce/monitor/aid in CSF circulation
For BBB/CSF barrier

256
Q

Function of Schwann cells

A

Myelinate axons in PNS

257
Q

Function of satellite cells

A

Second type of PNS neuroglia

Structural support and regulate materials between neuronal cell bodies and intersticial fluid

258
Q

Difference in replication of nervous system cells

A

Neurons- no mitosis

Neuroglial cells- do mitosis

259
Q

Define glioma

A

brain tumor of glia

includes astrocytomas, oligodendrogliomas, and schwannomas

260
Q

What two cells perform myelination?

A

Schwann-PNS

Oligodendrocytes- CNS

261
Q

Define myelin

What is their function?

A

multi-layered complex of lipids and proteins (layers of plasma membranes)

Prevent loss of electrical signal and speeds nerve impulse conduction

262
Q

What type of cell is a Schwann cell?

A

neurolemmocyte

263
Q

Myelination cells can be associated w/ unmyelinated cells. What is required for myelination?

A

Glial cell to wrap its plasma membrane around the axon several times, covers 1mm

264
Q

Define neurolemma

A

Outer nucleated cytoplasmic layer of Schwann cell which encloses myelin sheath
Found only around axons in PNS

265
Q

How are unmyelinated axons associated w/ Schwann cells?

A

Axons lay in grooves on surfaces of Schwann cells, no myelin sheath and no neurolemma

266
Q

What happens to the nucleus of the Schwann cell during the myelination process?

A

Neurolemmocyte nucleus ends in the neurolemma (outer nucleated cytoplasmic layer of the Schwann cell)

267
Q

Define Nodes of Ranvier

A

Only located on nerve fibers supplied by potentially myelin-producing cells
Gaps between myelinating cells
Found in both C/PNS

268
Q

What does a nerve fiber consist of?

A

Axon and myelin sheath

Endoneurim surrounds nerve fiber (this includes Schwann cells)

269
Q

How is myelination in the CNS achieved?

A

Oligodendrocytes- can myelinate several segments of one axon or myelinate several axons

270
Q

What structure is not present in CNS myelination?

A

Neurolemma, oligodendrocyte cell body and nucleus do not envelop axon

271
Q

What is the difference between gray and white matter in CNS?

A

White: predominantly filled w/ myelinated tract fibers, white due to myelin

Gray: predominantly filled w/ neuronal cell bodies, Nissi bodies provide gray color since there is no myelin

272
Q

What are the two types of electrical signals used by neurons to communicate?

A

AP: (nerve impulses), for short and long term communication, :all or none”

Graded potential: short distance/localized communication. A/effects generation of AP, not “all or none”

273
Q

AP and graded potentials depend on what two features of the plasma membrane?

A

Existence of a resting membrane potential

Specific ion channels

274
Q

Where is voltage measured?

A

Across plasma membrane, relative to outside of the cell

275
Q

Where are the nodes of a microelectrode placed?

A

Recording: inside neuron
Reference: ECF

276
Q

If opposite charges are separated in space, what is the potential?

A

Their attractive force= potential

Measured in Volts

277
Q

Define current

A

Flow of charged atoms or molecules
Electrical current: flow of e-
Body: current means flow of ions

278
Q

What gives the cells the property of electrical excitability?

A

Ion channels in plasma membrane of neurons and muscle fibers

279
Q

Types of ion channels and their characteristics

A

Leakage: randomly open/close; more for K+ than Na+; resting membrane is more K+ permeable

Ligand gated: bound to by ligand, controls open/close

Mechanical gated: open in response to mechanical stimuli (tension due to pressure)

Voltage gated: open/close in response to changed in membrane potential

280
Q

Define resting membrane potential

A

Voltage difference across plasma membrane when neuron is NOT signaling

Membrane is polarized

281
Q

How is resting membrane potential reported?

What is the range and average (mV) of the potential?

A

Reported as the potential of INSIDE of membrane relative to OUTSIDE of membrane

Range: -40mV - -90mV w/ -70 average

282
Q

What causes the resting membrane potential?

A

Anion build up in cytosol

Cation build up in ECF

283
Q

What ions are in higher concentration in ECF?

What ions are in higher concentration in the ICF?

A

ECF: Na and CL
ICF: K, organic phosphates, aa and proteins

284
Q

Resting membrane is ___-___x more permeable to _ than to _

A

50-100x
K+ than to Na
Cl is in between

285
Q

Membrane is impermeable to all of what molecule?

A

negatively charged intracellular molecules

286
Q

What two channels produce graded potentials in response to stimuli?

A

Ligand gated

Mechanical gated

287
Q

What does “graded” mean in graded potential?

A

Size of the change in the membrane potential varies in proportion to strength of stimulus (all-or-none)

288
Q

How far to graded potentials travel?

A

Short distance then diminishes to zero

289
Q

Define hyperpolarization

Define depolarization

A

Hyper: membrane is more polarized (more negative)

Depol: less polarized (less neg, more pos)

290
Q

Depolarization opens what ion channels?

Repolarization opens what ion channels?

Resting state has what channels open/close?

A

Na+, depolarization to -55mB threshold

Opens K+, closes Na+

Resting: K+ closed

291
Q

What effect does Ca+ have on the electrical state of a channel protein?

A

Pos charge of Ca+ increases voltage level required to open the gate

292
Q

What happens during calcium ion deficit

A

Ca deficit, Na channels activated by very little change of membrane potential

Nerve fibers become highly excitable, sometimes w/out provocation and not remaining in resting state

293
Q

Why is calcium ion deficit dangerous?

A

Low Ca= muscle contraction/cramps, tetany

Tetanic contraction of respiratory muscles can be fatal

294
Q

Where is the trigger zone of nerve impulses?

A

Axon hillock

295
Q

Define propagation

What is it dependent upon?

A

aka conduction
nerve impulse movement down neuron to axon terminals

Dependent on positive feedback

296
Q

What are the types of conduction?

A

Continuous: step by step depol/repol of adjacent segments

Saltatory: special mode occurring only along myelinated axons, faster and more energy efficient

297
Q

Where are voltage gated channels concentrated?

A

Nodes of Ranvier

298
Q

How do neurons produce their ATP?

A

Mostly: aerobic metabolism of glucose

299
Q

How is most of the brain’s energy consumption used?

A

Sustaining electrical charge of neurons

300
Q

Effect of axon diameter through A, B and C fibers

A

A: Large, myelinated
B: medium, myelinated
C: small, unmyelinated

301
Q

What two mechanisms enable stimuli of different intensities to be registered?

A

Frequency

Number of sensory neurons activated

302
Q

How does intensity perception get conveyed into impulses?

A

Frequency: light touch= low frequency

Number: firm pressure stimulates more pressure neurons

303
Q

What stimulus does not generate an AP?

A

sub-threshold stimulus

304
Q

Define synapse

A

junction between two neurons

junction between neuron and an effector (muscle or gland)

305
Q

What are the 3 common types of chemical synapses

A

Axodendritic- axon to dendrite
Axosomatic- axon to soma
Axoaxonic- axon to axon

306
Q

Difference between electrical and chemical synapse

A

Electrical: physically touch, AP moves through as ions flow

Chemical: do not touch, neurotransmitter bridges gap and allows AP to travel

307
Q

How are action potentials conducted between adjacent cells?

A

Gap junctions

Hundreds of connexons per gap junction connect cytosol

308
Q

Where are electrical synapses found?

A

Heart muscle fibers

Visceral smooth muscle

309
Q

Neurotransmitters that cause hyperpolarization of the postsynaptic membrane are ______

A

inhibitory

310
Q

Excitatory postsynaptic potential typically result from opening of what kind of channels?

A

ligand-gated CATION channels

Na, K and Ca

311
Q

Does one EPSP initiate a nerve impulse?

A

No, but becomes more excitable and more likely to reach threshold since it’s partially depolarized

312
Q

Difference between EPSP and IPSP

A

IPSP: opening of ligand gated ANION channel for Cl or ligand gated K

313
Q

What would happen if a neurotransmitter was not removed from a synaptic cleft?

A

Continuous influence of postsynaptic neuron/fiber/gland

314
Q

How are neurotransmitters removed?

A

Diffusion
Degradation- Acetylcholine broken down to acetyl and choline by acetycholinesterase
Cell uptake: reuptake if taken by same cell that released; uptake if taken back by cell that didn’t release originally

315
Q

Define neurotransmitter transporters

A

Membrane proteins that accomplish neurotransmitter uptake

316
Q

Define Spatial summation

A

Neurotransmitter builds up and released simultaneously by presynaptic end bulbs

317
Q

Define Temporal Summation

A

Neurotransmitter buildup and released by single presynaptic end build many times in succession

318
Q

Look at slide 17

A

Analyze

319
Q

What are the two classes of neurotransmitters?

A

Small molecule

Neuropeptides

320
Q

What are the small molecule neurotransmitters?

A
Acetylcholine
Amino acids
Biogenic amines
ATP/purines
Nitric oxide
321
Q

What kind of junctions does ACh open?

A

@ neuromuscular junctions, opens ligand-gated CATion channels

322
Q

Where is ACH released from?

A

Many PNS neurons

Some CNS neurons

323
Q

What are the two most common excitatory examples of amino acids?

Most common inhibitory?

A

Glutamate (glutamic acid)
Aspartate (aspartic acid)

Inhib: aminobutyric acid (GABA) and glycine

324
Q

Where are exogenous amines absorbed?

A

Directly by intestines

325
Q

Biogenic amines as neurotransmitters are generally associated with ____
and produce what kind of stimulus

A

Brain
Excitatory or inhibitory

Naming and categories, not BioChem heavy

326
Q

What are the classical monoamine neurotransmitters

A

Histamine- arousal/attention and pro-inflammatory
Serotonin- sensory perception, temp regulation, mood/sleep and appetite
Catecholamine neurotransmitters

327
Q

What are the catecholamine neurotransmitters

A

Dopamine- emotional response, addiction, pleasure, skeletal muscle tone/contraction
Norepinephrine- wakening from deep sleep, dreaming, mood regulation
Epinephrine- used by brain neurons

328
Q

Where is norepinephrine made?

A

adrenal medulla

329
Q

Where is NO gas made?

A

Endothelial cells in vessel walls
Lipid soluble, diffuses->smooth muscles causing vasodilation
Produced on demand

330
Q

Characteristics of neuropeptides

A

Short chain AA linked by peptide bonds
In both CNS and PNS
Excitatory and inhibitory
Formed in neuron body, packed in vesicles, transported to axon terminals
As hormones, regulate physiological responses

331
Q

What are the opioid peptides?

A

Enkephalins
Endorphins
Dynorphins
Body’s natural pain killers

332
Q

Define neural circuit

A

billions of neurons in CNS that are a functional group that process specific kind of information

333
Q

Define simple series circuit

A

One presynaptic neuron, stimulates one post-synaptic neuron which stimulates another

334
Q

Define diverging circuit

A

AP diverges which amplifies original signal

Sensory signals

335
Q

Define converging circuit

A

AP convergence
More effective stimulation/inhibition
Motor neuron->skeletal muscles

336
Q

Define reverberating circuit

A

Branches from subsequent stimulate neurons loop back and form a circuit
Can last seconds->hrs
Breathing, waking up, short-term memory

337
Q

Define parallel after-discharge circuit

A

One input w/ one output neuron and variable intermediate neurons

338
Q

Define plasticity

A

NS ability to change based on experience and need

339
Q

How can neurons change during plasticity?

A

New dendrites
Synthesize new proteins
Nature/number of synapses

340
Q

How can PNS perform repair/regeneration?

A

Dendrites and myelinated axons can undergo repair if cell body remains intact and myelinating Schwann cell is still active

341
Q

How does the sheath of Schwann conduct repairs?

A

Neurolemma forms regeneration tube to guide/stimulate axon regrowth

342
Q

In myelinated axons, voltage gated channels are concentrated around what structures?

A

Nodes of Ranvier

343
Q

What happens if the myelin sheath is destroyed?

A

Current can’t spread as far and can’t reach next group of voltage-gated channels

344
Q

Two disease examples of myelin destruction

A

Guillain-Barre Syndrome: PNS (result of bacteria infection)

Multiple Sclerosis: CNS (autoimmune)

345
Q

Epileptic seizures are commonly called what other name?

What is their most common cause?

A

electrical storm

Brain damage at birth

346
Q

What is rabies considered a fatal disease?

A

Virus reaches CNS by fast axonal transport

347
Q

How do local anesthetics produce their desired effect?

A

Block opening of voltage gated Na channels, prevents transmission of pain signals