Test 2 (Final) Flashcards Preview

Spring of 2012 > Test 2 (Final) > Flashcards

Flashcards in Test 2 (Final) Deck (109)
Loading flashcards...
0
Q

This reversal is due to changes in membrane permeability

A

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+

1
Q

There are _______ chemically and voltage gated channels on the sarcolemma.

A

Many

2
Q

Both channel types are

A

Highly specific for what ion is allowed to pass through

3
Q

Depolarization

A

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
Q

In nerve and skeletal tissue

A

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

Occurs at RMP, the cell is polarized

5
Q

Full AP

A
  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
Q

Chemically gated ion channels

A

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
Q

Muscle contraction is the summation of

A

Many APs (all phases)

8
Q

At about the same time that Na+ channels close

A

K+ channels open

9
Q

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

A

It’s concentration gradient (always down)

10
Q

Voltage gated ion channel

A

Open or close in response to voltage changes

membrane becoming more positive or negative

11
Q

Hyperpolarization

A

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

12
Q

Repolarization

A

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

13
Q

AP trace

A

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
Q

Permeability changes are due to

A

The opening of protien ion channels in the membrane

15
Q

AP

A

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

16
Q

Excitable tissue

A

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

17
Q

Epimysium

A

Dense connective tissue layer around the whole muscle

Also called fascia

18
Q

Microscopic general characteristics

A

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

19
Q

Motor unit

A

One motor neuron + all the muscle fibers it innervates

20
Q

Perimysium

A

CT covering around the bundles of muscle fibers called fasciles

21
Q

Sarcoplasm

A

Intracellular fluid

Contains glycosomes and myoglobin

22
Q

Tropomyosin

A

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

23
Q

General functions of muscle

A

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
Q

Glycosomes

A

Store glycogen for energy

25
Q

Hinge region

A

Junction of the head and the tail

Allows the head to bend and straighten during contraction

26
Q

Transverse tubule (T-Tubule)

A

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
Q

Gross anatomy

A

Connective tissue

Neural innervation

28
Q

Sarcomer

A

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
Q

Sarcolemma

A

Plasma membrane

30
Q

Actin

A

Each myofilament is made of:
Tropomyosin
Troponin
F-actin

31
Q

Anaerobic respiration/glycolysis

A

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
Q

Troponin

A

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
Q

Muscle metabolism

A

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

34
Q

M line

A

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

35
Q

Neuromuscular junction

A

The contact between the axon terminal and the muscle

36
Q

Functions of ATP

A

Contraction

Relaxation

37
Q

Myofibrils

A

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

38
Q

Motor neuron

A

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

39
Q

H zone

A

Band in the middle of the A band

Myosin only

40
Q

Contraction

A

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
Q

Aerobic respiration/oxidative phosphorylation

A

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
Q

Relaxation

A

Powers the pump that removes Ca+2 from the sarcomere

43
Q

Binding site for actin

A

Has ATPase activity

Splits an ATP to yield ADP, Pi, and energy

44
Q

Endomysium

A

Reticular CT that surrounds each of the fibers in the fascile

45
Q

Sarcoplasmic reticulum (SR)

A

Surrounds each myofibril

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

46
Q

Myofilaments

A

Action (thin filament)

Myosin (thick filament)

47
Q

General characteristics of muscle

A

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

48
Q

F-actin

A

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

49
Q

G-actin

A

Small globular protiens

Has an active site to which myosin binds during contraction

50
Q

I bands

A

Light bands consisting of actin only

51
Q

Connective tissue

A

Epimysium
Perimysium
Endomysium

52
Q

Direct phosphorylation of ADP by creatine phosphate (CP)

A
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
Q

Myosin

A

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
Q

A bands

A

Dark bands consisting of actin and myosin

55
Q

Z-disk/line

A

Protien attachment site for the actin

56
Q

Myoglobin

A

Red pigmented oxygen storing protien

57
Q

Symphyses

A

2 bones joined by fibrocartilage
Flexible, some movement can occur

Ex: pubic symphyses
Intervertebral disc

58
Q

Fibrous joints

A

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

Three classifications:
Sutures
Syndesmoses
Gamphoses

59
Q

Synchondroses

A

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
Q

Gamphoses

A

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

Ex: between teeth and mandible and maxilla

61
Q

Cartilaginous joints

A

Two bones united together by hyaline cartilage or fibro cartilage

Two classifications:
synchondroses
Symphyses

62
Q

Classes of joints

A

Fibrous
Cartilaginous
Synovial

63
Q

Sutures

A

Seams between skull bones
Very stable
Opposing bones have interlocking processes

Ex: coronal suture between frontal and parietal bone

64
Q

Syndesmoses

A

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

Ex: tibiofibular joint

65
Q

Periosteum

A

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

66
Q

Fontanels

A

Fibrous membranes holding the bones of the skull together before ossification

67
Q

Appositional growth

A

Growth from the outside

Chondroblasts lay down new matrix on the outside of the tissue

68
Q

Chondrocyte

A

When the secreted matrix surrounds the condroblast

It matures

69
Q

Epiphysis

A

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

70
Q

4 bone shapes

A

Long
Short
Flat
Irregular

71
Q

Irregular bones

A

Odd shaped

Vertebrae, patella

72
Q

Haversian canal

A

Passage way for blood vessels and nerves

Compact bone

73
Q

Lamellae

A

Circular layers of the bone matrix

Compact bone

74
Q

Appendicular skeleton

A

Function: movement

Upper and lower limbs, shoulder and pelvic girdles

75
Q

Vitamin D

A

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
Q

Diaphysis

A

Shaft that forms the long axis

Formed mostly of compact bone

77
Q

Zone of resting cartilage

A

Nearest to the epiphysis

Contains randomly arranged chondrocytes that are slowly dividing

78
Q

Scurvy

A

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

79
Q

Zone of hypertrophy

A

3rd

Chondrocytes produced in zone 2 (proliferation) mature and enlarge

80
Q

Parathyroid hormone

A

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
Q

Medullary cavity

A

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

82
Q

Osteoclot

A

Bone resorbing cell

83
Q

Epiphyseal plate

A

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
Q

Bone growth

A

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

85
Q

Flat bones

A

Thin, flat, usually curved

Some skull bones, sternum, ribs, scapula

86
Q

Calcitonin

A

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
Q

Zone of calcification

A

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
Q

Osteon

A

The structural unit of Compact bone

89
Q

Axial skeleton

A

Function: protection and support

Skull, rib cage, vertebral column

90
Q

Osteoblast

A

Bone forming cell

91
Q

Lacunae

A

The space a chondrocyte occupies

92
Q

Zone of proliferation

A

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

93
Q

Osteomalacia

A

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

94
Q

Long bone structure

A
Diaphysis
Epiphysis
Epiphyseal plate
Medullary cavity
Periosteum
Endosteum
95
Q

4 zones of the epiphyseal plate

A

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

96
Q

Long bones

A

Longer than they are wide

Most bones of the upper and lower limbs

97
Q

Vitamin C

A

Necessary for collagen synthesis by osteoblasts

Deficiency can result in scurvy

98
Q

Sharpey’s fibers

A

Secure tendons and ligaments to periosteum

99
Q

Factors affecting bone growth

A

Nutrition

Hormones

100
Q

Canaliculi

A

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
Q

Hormone at regulate the exchange of calcium between blood and bone

A

Calcitonin

Parathyroid hormone

102
Q

Osteoporosis

A

Brittle bones due to a decrease in Ca+2 deposition

103
Q

General bone characteristics

A

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

104
Q

Short bones

A

As wide ass they are long

Bones of the wrist and ankle

105
Q

Cartilage

A

Consists of special cells called chondroblasts that produce new cartilage matrix

106
Q

Endosteum

A

CT membrane lining inner bone surfaces

107
Q

Rickets

A

A disease resulting from reduced mineralization of the bone matrix

Causes bones to “bow”

108
Q

Interstitial growth

A

Growth from the inside

Inner chondrocytes rapidly divide, expanding the cartilage from within

Decks in Spring of 2012 Class (56):