Muscle Tissue (Ch 10) Flashcards Preview

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Flashcards in Muscle Tissue (Ch 10) Deck (28):
1

What are the types of muscle tissue?

1. skeletal
2. cardiac
3. smooth

2

Skeletal Muscle

pulls on bones of skeleton
-striated
-voluntary

3

Cardiac Muscle

pushes blood through the circulatory system
-striated
-involuntary

4

Smooth Muscle

pushes fluids/solids along the digestive tract and regulates the diameters of small arteries
-not striated
-involuntary

5

What are the properties of skeletal muscle tissue?

-contractility: muscle cells can shorten
-excitability: very responsive
-extensibility: can increase in length
-elasticity: able to return to original length

6

What are the functions of skeletal muscle?

1. produce movement
2. maintain posture
3. support
4. generate heat
5. storage and movement of materials

7

What does skeletal muscle contain?

skeletal muscle + CT + nerves + blood vessels

8

What are the subdivisons of skeletal muscle?

muscle --> fascicle --> muscle fiber

9

What are the connective tissue membranes?

-epimysium
-perimysium
-endomysium

10

Epimysium

*CT membrane
-surrounds entire "muscle," separates muscle from surrounding tissues and organs

11

Perimysium

*CT membrane
-surrounds each fascicle --> divides skeletal muscle into compartments

12

Endomysium

*CT membrane
-surrounds muscle fibers within a fascicle

13

What are the muscle attachments?

tendons: muscle to bone
aponeurosis: flat sheets of tendons

14

Origin

proximal attachment to bone (fixed)

15

Insertion

distal attachment to bone (mobile)

16

What are the types of fascicle orientations?

1. Circular
2. Convergent
3. Parallel
4. Pennate

17

Circular Fascicle Orientation

-surround external body openings
-sphincter
-close when they contract
--> ex. orbicularis oris, orbicularis oculi

18

Convergent Fascicle Orientation

-broad origin
-narrow insertion
-direction of pull can be changed because different groups of fibers can be activated
-->ex. pectoralis major, latissimus dorsi, gluteus medius

19

Parallel Fascicle Orientation

-fascicles run parallel to long axis of muscle
-tapered at both ends
-strap
-high endurance, not very strong
-->ex. sternocleidomastoid, brachioradialis, flexor digitorum superficialis (FDS)

20

Pennate Fascicle Orientation

-fascicles short
-attach obliquely to tendon or raphe
-uni-, bi-, multipennate
-stronger than parallel muscle of same size
-->ex. rectus femoris (bi-), extensor digitorum longus (uni-), deltoid (multi)

21

Muscle Compartments

-dense, fibrous CT divides muscles into compartments
-same compartment? = similar actions
-different compartment? = opposite actions
-usually muscles in same compartment are innervated by a single nerve

22

Compartment Syndrome

-damaged muscle swells --> surrounding fascia (inelastic) constricts
-puts pressure on vessicles and nerves (=PAIN), also prevents blood from entering/draining
--> acute vs. chronic

23

Acute Compartment Syndrome

-from accident/injury
-can lead to tissue loss in muscle or limb due to loss of blood supply

24

Chronic Compartment Syndrome

caused by overuse
--> rest until it heals

25

How do we name muscles?

1. Location (ex. biceps brachii)
2. Shape (ex. deltoid = triangular)
3. Relative Size (ex. gluteus maximus = largest)
4. Direction of Fascicles/Fibers (ex. external oblique)
5. Direction of Attachments (ex. coracobrachialis = corocoid process and brachium)
6. Number of Origins/Heads (ex. biceps brachii = two heads)
7. Action (ex. flexor digitorum longus)

26

Myofibril

-->contractile portion of muscle fiber
-there are 100s-1000s of myofibrils in each skeletal muscle fiber
-along length of myofibril are sarcomeres (repeating segments)

27

Sarcomere

-->basic functional unit of skeletal muscle
-contraction = contraction of muscle
-extends from Z disc to Z disc (A band)
-up to 10,000 per myofibril
-center = M line
-made of thick (myosin) filaments and thin (actin) filaments

28

Sliding Filament Mechanisms

thin (myosin) and thick (actin) filaments slide past each other