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Flashcards in Test 2 (Final) Deck (109):
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There are _______ chemically and voltage gated channels on the sarcolemma.

Many

1

This reversal is due to changes in membrane permeability

At RMP the membrane is more permeable to K+ than it is to Na+
To generate an AP the membrane becomes more permeable to Na+
To end the AP (so a new one can be generated) the membrane again becomes more permeable to K+

2

Both channel types are

Highly specific for what ion is allowed to pass through

3

Depolarization

Na+ will Move down its concentration gradient into the cell (Na+ influx)
Na+ brings its positive charge with it, creating intracellular positivity

When Na+ channels close influx stops

4

In nerve and skeletal tissue

An excitatory stimulus (chemical binding or voltage change) will cause Na+ channels to open

Occurs at RMP, the cell is polarized

5

Full AP

1. Cell is at RMP, then receives an excitatory stimulus
2. Voltage opens some Na+ channels; allowing Na+ influx and the cell gradually becomes more positive/less negative
3. Voltage allows many Na+ channels to open; allowing an increase in Na+ influx creating a steep incline (spike potential)
4. Na+ channels close and K+ channels open, allowing K+ eflux; the cell becomes more negative/less positive
5. Excess K+ eflux
6. The Na+/K+ pump begins to actively pull K+ back into the cell to restore RMP

6

Chemically gated ion channels

Open or close when a chemical binds to a protien receptor that is part of the ion channel

Ex: Ach (Acetylcholine) is a neurotransmitter that causes Na+ channels to open

7

Muscle contraction is the summation of

Many APs (all phases)

8

At about the same time that Na+ channels close

K+ channels open

9

The ion will move into or out of the cell based on

It's concentration gradient (always down)

10

Voltage gated ion channel

Open or close in response to voltage changes
(membrane becoming more positive or negative)

11

Hyperpolarization

A brief period when excess K+ leaves the cell and the membrane temporarily becomes more negative than it was at rest

12

Repolarization

K+ will move down its concentration gradient out of the cell (K+ eflux)
K+ takes its positive charge with it creating intracellular negativity

13

AP trace

Represents the voltage across the cell membrane
Measured by comparing the charge of the ICF to the ECF

Technique is called "patch clamping"
Branch of science is called "electrophysiology"

14

Permeability changes are due to

The opening of protien ion channels in the membrane

15

AP

The reversal of the resting membrane potential such that the inside of the cell becomes more positive

16

Excitable tissue

Only contracts in response to electrical activity on the surface of the muscle cell membrane

17

Epimysium

Dense connective tissue layer around the whole muscle
Also called fascia

18

Microscopic general characteristics

Each fiber is a long cylindrical cell with multiple oval nuclei
Each muscle fiber is made of many myofibrils

19

Motor unit

One motor neuron + all the muscle fibers it innervates

20

Perimysium

CT covering around the bundles of muscle fibers called fasciles

21

Sarcoplasm

Intracellular fluid
Contains glycosomes and myoglobin

22

Tropomyosin

Stabilizing protien that winds along a groove in the F-actin strand

23

General functions of muscle

Body movement (skeletal)
Maintenance of posture (skeletal)
Production of heat as a by product of activity (all)
Constriction of organs and blood vessels (smooth)
Production of heart beat (cardiac)

24

Glycosomes

Store glycogen for energy

25

Hinge region

Junction of the head and the tail
Allows the head to bend and straighten during contraction

26

Transverse tubule (T-Tubule)

Invagination of the muscle cell sarcolemma
Runs between lateral spaces to form a triad (1 t tubule+2 lateral sacs= a triad)
Functions to quickly transmit AP through out the muscle cell

The AP signals the release of Ca+2 from the lateral sacs

27

Gross anatomy

Connective tissue
Neural innervation

28

Sarcomer

Structural units of actin and myosin
Functional unit of a muscle

Extends from one Z-disk to another
Striations can be seen under a microscope due to alternating light and dark bands

A bands
I bands
H zone
M line

29

Sarcolemma

Plasma membrane

30

Actin

Each myofilament is made of:
Tropomyosin
Troponin
F-actin

31

Anaerobic respiration/glycolysis

Does not require O2
Involves catabolism of glucose that has been obtained from the blood stream or from the breakdown of glycogen stores in the muscles (within glycosomes)
Reaction: the glucose is broken down into ATP and pyruvic acid
Yield: 2 ATP per 1 glucose
About 30-60 seconds of activity

32

Troponin

3 polypeptide complex

TnI bonds to G-actin
TnT binds to tropomyosin, anchoring it to the F-actin strand
TnC binds to Ca+2

33

Muscle metabolism

Continuous muscle contraction requires continuous ATP production
Accomplished via 3 pathways:
Direct phosphorylation
Anaerobic respiration/glycolysis
Aerobic respiration/oxidative phosphorylation

34

M line

One in the middle of the H zone that holds the myosin in place

35

Neuromuscular junction

The contact between the axon terminal and the muscle

36

Functions of ATP

Contraction
Relaxation

37

Myofibrils

Thread like structures that extend from one end of the muscle to the other
Made of myofilaments

38

Motor neuron

Specialized nerve cells
Somas are in the spinal cord
Axons extend to muscle fibers
Function: electrically stimulate the muscles to contract

39

H zone

Band in the middle of the A band
Myosin only

40

Contraction

Powers the ratcheting movement of the myosin head
After each ratcheting movement a new ATP molecule binds to the myosin head so it can detach, then bind again to the next G-actin molecule

41

Aerobic respiration/oxidative phosphorylation

Requires O2
Pyruvic acid from glycolysis is transferred to the Kreb's cycle
Within mitochondria high energy bonds are broken and ATP is released
Yield: 34 ATP per 1 glucose
Hours at activity

+ the 2 from glycolysis

42

Relaxation

Powers the pump that removes Ca+2 from the sarcomere

43

Binding site for actin

Has ATPase activity
Splits an ATP to yield ADP, Pi, and energy

44

Endomysium

Reticular CT that surrounds each of the fibers in the fascile

45

Sarcoplasmic reticulum (SR)

Surrounds each myofibril
Upon electrical stimulation it releases Ca+2 from the lateral sacs

46

Myofilaments

Action (thin filament)
Myosin (thick filament)

47

General characteristics of muscle

Excitable tissue
Contracts
Relaxes
Makes up about 40% of the average persons body mass

48

F-actin

Fibrous actin
Coiled to form a double helix
Made of 200 G-actin

49

G-actin

Small globular protiens
Has an active site to which myosin binds during contraction

50

I bands

Light bands consisting of actin only

51

Connective tissue

Epimysium
Perimysium
Endomysium

52

Direct phosphorylation of ADP by creatine phosphate (CP)

CP is an extremely high energy molecule that is stored in muscle
1st source of energy
Reaction:
Creatine phosphate + ADP= creatine + ATP
Enzyme: creatine kinase
Yield: 1 ATP per creatine phosphate
About 15 seconds of activity

53

Myosin

Each filament has:
a rod like tail consisting of two entwined polypeptide chains
Two heads that have three components each

Binding site for actin
Binding site for ATP
Hinge region

54

A bands

Dark bands consisting of actin and myosin

55

Z-disk/line

Protien attachment site for the actin

56

Myoglobin

Red pigmented oxygen storing protien

57

Symphyses

2 bones joined by fibrocartilage
Flexible, some movement can occur

Ex: pubic symphyses
Intervertebral disc

58

Fibrous joints

2 bones are united by fibrous CT
Exhibit very little to no movement at all

Three classifications:
Sutures
Syndesmoses
Gamphoses

59

Synchondroses

2 bone suited by hyaline cartilage
Little to no movement

Ex: epiphyseal plate
Between the costal cartilage of the 1st rib and the manubrium

60

Gamphoses

Specialized joints consisting of pegs and sockets
Held together by CT tissue called periodontal ligaments

Ex: between teeth and mandible and maxilla

61

Cartilaginous joints

Two bones united together by hyaline cartilage or fibro cartilage

Two classifications:
synchondroses
Symphyses

62

Classes of joints

Fibrous
Cartilaginous
Synovial

63

Sutures

Seams between skull bones
Very stable
Opposing bones have interlocking processes

Ex: coronal suture between frontal and parietal bone

64

Syndesmoses

Joins bones to a ligament
Flexible, so some movement can occur

Ex: tibiofibular joint

65

Periosteum

CT membrane covering the outer surface of bone
Outermost: dense, irregular CT
Innermost: osteoblasts, osteoclots
Sharpey's fibers

66

Fontanels

Fibrous membranes holding the bones of the skull together before ossification

67

Appositional growth

Growth from the outside

Chondroblasts lay down new matrix on the outside of the tissue

68

Chondrocyte

When the secreted matrix surrounds the condroblast
It matures

69

Epiphysis

Knobs on the end of long bones
Composed mostly of spongy/cancellous bone
Outer covering of compact bone

70

4 bone shapes

Long
Short
Flat
Irregular

71

Irregular bones

Odd shaped
Vertebrae, patella

72

Haversian canal

Passage way for blood vessels and nerves

Compact bone

73

Lamellae

Circular layers of the bone matrix

Compact bone

74

Appendicular skeleton

Function: movement

Upper and lower limbs, shoulder and pelvic girdles

75

Vitamin D

Needed for absorption of Ca+2 from the small intestine

Deficiency in children can lead to rickets
Adults with the inability to metabolize vitamin D can develop osteomalacia

76

Diaphysis

Shaft that forms the long axis
Formed mostly of compact bone

77

Zone of resting cartilage

Nearest to the epiphysis
Contains randomly arranged chondrocytes that are slowly dividing

78

Scurvy

Characterized by ulceration and hemorrhage of skin because of lack of normal collagen in CT

79

Zone of hypertrophy

3rd
Chondrocytes produced in zone 2 (proliferation) mature and enlarge

80

Parathyroid hormone

Synthesized and secreted by the parathyroid gland
Signal for release is low plasma calcium levels
Mobilizes Ca+2 from the bone into the blood

81

Medullary cavity

In the diaphysis of the long bone
Children- contains red marrow
Adults- contains yellow marrow

82

Osteoclot

Bone resorbing cell

83

Epiphyseal plate

Hyaline cartilage between the epiphysis and the diaphysis
Area of growth
At the end of the growth it is transformed into bone and is called the epiphyseal line

84

Bone growth

Happens in length
New bone is formed on the surface of cartilage
Occurs at the epiphyseal plate

85

Flat bones

Thin, flat, usually curved
Some skull bones, sternum, ribs, scapula

86

Calcitonin

Synthesized and secreted by the thyroid gland
Promotes the incorporation of Ca+2 into bone from blood

Sensitive to estrogen levels
Lots of estrogen=lots of calcitonin release=lots of Ca+2 incorporated into the bone
Menopausal women may develop osteoporosis

87

Zone of calcification

Consists of cartilage matrix mineralized by Ca+2
Hypertrophied chondrocytes die
Blood vessels inner ate the area

CT surrounding blood vessels contain osteoblasts
They deposit new bone matrix on the surface of the calcified cartilage (appositional growth)

88

Osteon

The structural unit of Compact bone

89

Axial skeleton

Function: protection and support

Skull, rib cage, vertebral column

90

Osteoblast

Bone forming cell

91

Lacunae

The space a chondrocyte occupies

92

Zone of proliferation

2nd zone
Chondrocytes producing new cartilage through interstitial cartilage growth
Rapid division

93

Osteomalacia

Softening of the bones as a result of Ca+2 depletion

94

Long bone structure

Diaphysis
Epiphysis
Epiphyseal plate
Medullary cavity
Periosteum
Endosteum

95

4 zones of the epiphyseal plate

Zone of resting cartilage
Zone of proliferation
Zone of hypertrophy
Zone of calcification

96

Long bones

Longer than they are wide
Most bones of the upper and lower limbs

97

Vitamin C

Necessary for collagen synthesis by osteoblasts
Deficiency can result in scurvy

98

Sharpey's fibers

Secure tendons and ligaments to periosteum

99

Factors affecting bone growth

Nutrition
Hormones

100

Canaliculi

Small canals that connect the lamellae to each other and to the central haversian canal

Allows nutrient and waste exchange for the osteocytes

Compact bone

101

Hormone at regulate the exchange of calcium between blood and bone

Calcitonin
Parathyroid hormone

102

Osteoporosis

Brittle bones due to a decrease in Ca+2 deposition

103

General bone characteristics

206 named bones
Each bone is an organ
Made of living tissue (can grow and repair)

104

Short bones

As wide ass they are long
Bones of the wrist and ankle

105

Cartilage

Consists of special cells called chondroblasts that produce new cartilage matrix

106

Endosteum

CT membrane lining inner bone surfaces

107

Rickets

A disease resulting from reduced mineralization of the bone matrix

Causes bones to "bow"

108

Interstitial growth

Growth from the inside

Inner chondrocytes rapidly divide, expanding the cartilage from within

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