List #6 Flashcards Preview

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Flashcards in List #6 Deck (54):
1

fascia

-layers of dense connective tissue that holds individual skeletal muscle in position.

2

myosin

-thick protein filament (dark)

3

actin

-thin protein filament (light)

4

sacromeres

- The striations form a repeating pattern of units along tac muscle fiber

5

I-bands

- The light bands, composed of thin actin filaments held by direct attachments to structures called Z lines

6

Z-lines

-Found in the center of I-bands

7

H-zones

- A slightly lighter central region consisting only of thick filaments found in the A-band

8

A-bands

-The second part of the striation pattern, which composes thick myosin filaments overlapping thin actin filaments

9

M-lines

- Consists of proteins that help hold the thick filaments in place, found in the A band in a thicker section.

10

myosin crossbridges

-A myosin head can attach to an actin binding site forming a cross-bridge, and bend slightly, pulling on the actin filament

11

ATPases

- An enzyme found in myosin heads
- it catalyzes the breakdown of ATP to ADP and a phosphate

12

tropomyosin

-rod-shaped and occupy the longitudinal grooves of the actin helix

13

troponin

-three protein subunits and are attached to actin

14

sarcoplasmic reticulum

- corresponds to the endoplasmic reticulum. Membranous channels in the sarcoplasm of a muscle fiber that surrounds each myofibril and runs parallel to it.

15

transverse tubules

- A set of membranous channels that extends into the sarcoplasm as invaginations continuous with the sarcolemma and contains extracellular fluid

16

triads

-Region where the actin and myosin filaments overlap

17

sliding filament theory

- When sarcomeres shorten, the thick and thin filaments do not change length

18

neuromuscular junction

- The synapse where a motor neuron axon and a skeletal muscle fibers.
- Here the muscle fiber membrane is specialized to form a motor end plate, where nuclei and mitochondria are abundant and the sarcolemma is extensively folded.

19

lower motor neurons

-Neurons that control effectors, including skeletal muscle fibers.
-Normally a skeletal muscle fiber contracts only upon stimulation by its motor neuron

20

motor end plates

- Where nuclei and mitochondria are abundant and the sarcolemma is extensively folded.

21

motor unit

- Together a motor neuron and a muscle fiber control it

22

synaptic cleft

- A small gap that separates the membrane of the neuron and the membrane of the muscle fiber

23

neurotransmitters

- Biological messenger molecules that convey neural information

24

synaptic vesicles

-tiny vesicles that stores neurotransmitters

25

acetylcholine (ACh)

- The neurotransmitter that motor neurons use to control skeletal muscle contraction.

26

acetylcholinesterase

- An enzyme that rapidly decomposes acetylcholine remaining in the synapse.

27

myasthenia gravis

-grave muscular weakness
- The body produces antibodies that target receptors for the neurotransmitter acetylcholine on skeletal muscle cells at neuromuscular junctions

28

peristalsis

-Alternare contractions and relaxations of the longitudinal and circular muscles.
-In the intestines it pushes food down the digestive tract

29

dendrites

- Small cellular processes that receive input

30

axons

- A longer process than dendrites(nerve fiber) , and carries the information away from the cell in the form of impulses

31

cell body(perikaryon) of neuron

- It contains granular cytoplasm, mitochondria, lysosomes, a Golgi apparatus, and many microtubules.

32

chromatophilic substance (Nissl substance)

- consist mainly of rough endoplasmic reticulum

33

Schwan cells

-neuroglia that encase the large axons of peripheral neurons in lipid-rich sheaths (PNS)

34

myelin

- layers that consist of several types of lipids and proteins

35

nodes of Ranvier

-Narrow gaps in the myelin sheath between Schwann cells

36

trigger zone (axon hillock)

- In a multipolar neron, the first part of the axon the cone-shaped axon hillock or initial segment

37

astrocytes

- provide support and hold structures together with abundant cellular processes
- aid metabolism of certain substances, and they may help regulate the concentrations of important ions in the interstitial space of nervous tissues

38

oligodendrocytes

- A type of neuroglia that produces myelin rather than a Schwann cell. (CNS)

39

microglia

- Small cells that have fewer processes than other types of neuroglia

40

ependyma

- Cuboidal or columnar cells in shape and may have cilia.
- They form the inner lining of the central canal that extends downward through the spinal cord

41

ventricles

-Ependymal cells also form a one-cell-thick epithelial-like membrane that covers the inside of spaces in the brain

42

central canal

-Extends downward from the spinal cord

43

choroid plexuses

- Specialized capillaries associated with the ventricles of the brain
-They regulate the composition of the cerebrospinal fluid

44

buccinator

origin: Alveolar processes of maxilla and mandible
insertion: orbicularis oris
action: compresses cheeks

45

platysma

origin: Fascia in upper chest
insertion: skin and muscles below mouth; mandible
action: depresses lower lip and angle of mouth as when pouting

46

levator scapulae

origin: transverse processes of cervical vertebra
insertion: medial border of scapula
action: elevates scapula

47

pectoralis major

origin: clavicle, sternum, and costal cartilages of upper ribs
insertion: intertubercular groove
action: flexes shoulder, adducts, and rotates arm medially

48

coracobrachialis

origin: coracoid process of scapula
insertion: medial mid-shaft of humerus
action: flexes shoulder and adducts arm

49

teres major

origin: lateral border of scapula
insertion: intertubercular groove
action: extends shoulder, adducts, and rotates arm medially

50

subscapularis

origin: anterior surface of scapula
insertion: lesser tubercle of humerus
action: rotates are medially

51

infraspinatus

origin: infraspinous fossa of scapula
insertion: greater tubercle of humerus
action: rotates arm laterally

52

brachioradialis

origin: distal lateral end of humerus
insertion: lateral surface of radius above styloid process
action: flexes elbow

53

triceps brachii

origin: tubercle below glenoid cavity and lateral and posterior surfaces of the humerus
insertion: olecranon process of ulna
action: extends the elbow

54

plantaris

origin: femur
insertion: calcaneus
action: plantar flexion of foot, flexes knee