muscular system anatomy

Question 1

what does the muscular system include?

Answer 1

700+ skeletal muscles
tendons connect muscle to bone
aponeuroses

Question 2

what is the muscular system functions?

Answer 2

skeletal movement
maintains posture
stabilizes joints and supports organs
controls openings of urinary and digestive systems
generates heat
nutritional reserve protein storage

Question 3

what are the four basic properties in muscle tissue?

Answer 3

1.excitability- nerve impulses/hormones trigger action potential’s which causes muscle contraction
2. contractility- muscle tissue can shorten, exerts pull (tension) contratile proteins is actin and myosin
3. extendibility- can be stretched
4. elasticity- after stretching recoils to original length

Question 4

what are the three types of muscle tissue?

Answer 4

1.skeletal muscle\
2. smooth muscle
3. cardiac muscle

Question 5

what muscle tissue is muscular system?

Answer 5

skeletal muscle

Question 6

what are muscles?

Answer 6

bundles of muscle cells “fibres”

Question 7

what are the structures consisting of a muscle nerve?

Answer 7

1.epimysium- dense c.t surround muscle
2. fosicle- bundle of muscle fibres
3. perimysium- c.t surrounding fascicles
4. myofibril- contracts organalle
5. endomysium- c.t surrounding each muscle fibre
6. muscle fibres- muscle cell

Question 8

what does the c.t of perimysium and endomysium house?

Answer 8

houses blood vessels and nerves

Question 9

what may individual muscles be surrounded by and what is their purpose?

Answer 9

a fascia- which is layers of fibrous c.t that attaches/stabilizes/ encloses muscles and separates muscles from other structures and forms compartments

Question 10

how does a tendon attach to a bone?

Answer 10

at each end of a muscle the collagen fibres of the epimysium converge to form tendons (made of collagen and interwoven with collagen of periosteum)

Question 11

what are the four different fascicle arrangements?

Answer 11

parallel
pennate
convergent
circular

Question 12

what is fascicle arrangment?

Answer 12

fascicle arrangment varies and it reflects muscles actions/functions

Question 13

what is a parallel fascicle arrangement?

Answer 13

fascicles parallel to long axis
muscles can shorten a lot
ex. biceps brachii

Question 14

what is a pennate fascicle?

Answer 14

short fascicles attached to a long tendon
may be unipennate, bipennate, or multipennate
cant shorten as much nut many muscle fibres are powerful
ex. rectus femoris of quadriceps group

Question 15

what is a convergent (fan-shaped) fascicle?

Answer 15

widely spread fascicle converge towards a common tendon
direction of pull can change but less force overall
ex. pectoralis major

Question 16

what is a circular fascicle?

Answer 16

fascicles arranged in a circle “sphincter”
guard entrances/exit body
ex. orbicularis, urethral and anal sphincters

Question 17

what is a muscle cell?

Answer 17

muscle fibre

Question 18

what are characteristics of skeletal muscle fibres?

Answer 18

long, striated, multinucleiated cells
formed by fusion of many embryonic cells

Question 19

what is the sacolemma?

Answer 19

muscle cell membrane, c.t surrounding the entire muscle cell

Question 20

what is sacroplasm?

Answer 20

cytoplasm

Question 21

how do transverse tubules form?

Answer 21

sacrolemma penetrates cytoplasm to for t-tubules

Question 22

what do transverse tubules do?

Answer 22

spread electrical impulses aka action potencial

Question 23

what stores Ca++?

Answer 23

special endoplasmic reticulum - sacroplasmic reticulum

Question 24

what is a myofibril?

Answer 24

contractile organelle of muscle fibres
contains protein filaments

Question 25

what are the two protein filaments?

Answer 25

thin filaments- made of actin (globular actin forms filaments of f actin) +tropomyosin + troponin

thick filaments- made of myosin with a core of elastic titin (titin attaches myosin to Z-lines)

Question 26

what are the contractile units the myofibril is arranged into?

Answer 26

sacromeres, which shorten when contraction occurs, filaments slide