Muscle Tissue Flashcards Preview

BDS1 - BAMS - Histology > Muscle Tissue > Flashcards

Flashcards in Muscle Tissue Deck (32)
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1

How is muscle tissue classified

1. control
2. structure
3. muscle type

2

How is skeletal muscle classified

somatic (voluntary) & striated

3

How is cardiac muscle classified

autonomic (involuntary)
striated

4

How is smooth muscle classified

autonomic (involuntary)
non striated

5

What is the function of skeletal muscle

voluntary movement of skeleton
movement of eye/tongue
sub conscious movement to maintain posture and balance

6

What is the structure of skeletal muscle

elongated, unbranched cylindrical cells
multiple peripherally located nuclei
arrangement of contractile proteins (myofibrils causes striated appearance)

7

Describe the macroscopic structure of skeletal muscle

- individual muscle fibers are separated by endomysium
- groups of muscle fibers grouped together in fasciculi
- each fascicule is surrounded by loose connective tissue called perimysium
- entire muscle is externally surrounded by dense connective epimysium
- blood vessels and nerves spread throughout these connective tissue

8

Describe the cell structure of skeletal muscle

- each muscle cell is packed full of numerous myofibrils
- arrangement of myofibrils gives rise to the striated appearance

9

Describe which organelles are specialized for skeletal muscle

plasma membrane called sacrolemma
cytoplasm called the sacroplasm
sarcoplasmic reticulum
multinucleated

10

Describe the electron microscopy cell structure

sarcoplasm filled with myofibrils arranged in parallel
numerous mitochondria between myofibrils
microfibrils are composed of microfilaments
thick microfilaments composed of myosin - dark
thin microfilaments composed of actin - light
Z lines divide each myofibril into contractile units called sarcomeres which is the functional contracting unit of the muscle

11

What is the function of cardiac muscle

Specialized for continuous autonomous contractions
Pump blood through the cardiovascular system

12

Where is cardiac muscle found

in the heart

13

What is the structure of cardiac muscle

elongated, branched cylindrical cells
1 or 2 centrally located nuclei
similar arrangement of contractile proteins as in skeletal muscle causing striated appearance

14

What are the 3 layers of the heart wall

pericardium
myocardium
endocardium

15

What is the pericardium

outer supporting tissue layer

16

What is the myocardium

cardiac muscle tissue

17

What is the endocardium

single layer of endothelial cells

18

Describe the histological structure of cardiac muscle

Individual cardiac muscle fibers surrounded by reticular connective tissue
Supports rich capillary network

19

What are intercalated discs

specialized intercellular junctions that anchor adjacent cardiac cells together

20

What are the similarities between cardiac muscle and skeletal muscle

identical arrangement of sarcomeres
contain t tubules and sarcoplasmic reticulum
numerous mitochondria
glycogen and lipid granules present
contraction by sliding filament mechanism

21

What are the differences between skeletal muscle and cardiac muscle

autonomous contraction
sarcoplasmic reticulum slowly leaks calcium
intercalated discs which propagate the action potential
has modified cardiac muscle cells known as the conducting system
modulated by external autonomic/hormonal stimuli

22

What is the pace maker of the heart

sinoatrial node

23

How is the rate of inherent rhythm modulated

by:
autonomic nervous stimulation
hormonal stimulation

24

How do the modified cardiac muscles in the conducting system differ

fewer myofibrils
no T tubules, no intercalated discs

25

What is the function of smooth muscle

Specialized for continuous contractions

26

Where is smooth muscle found

lining hollow organs

27

What is the structure of smooth muscle

small, elongated, spindle shaped cells with tapered ends
single, centrally located nuclei
no sarcomeres so no striations

28

how is actin and myosin anchored to smooth muscle

focal densities

29

what is endomysium

fibrous material between the muscle fibres is called the endomysium - the endomysium may also contain blood capillaries

30

what is the perimysium

Clusters of fibres are bound together by support tissue called perimysium to form fascicles - in the perimysium there may be larger vessels