MUSCULAR SYSTEM

Question 1

what are the types of muscular tissue

Answer 1

skeletal
cardiac
smooth

Question 2

what does the muscular system do

Answer 2

convert chemical energy (ATP) into mechanical energy for movement

Question 3

what are the functions of muscles

Answer 3

movement
stability
control of body and opening passages
heat production

Question 4

movement of muscles

Answer 4

they enable us to move. muscular contractions also move body contents in course of breathing, blood circulation, feeding and digestion, defecation, urination and childbirth. they also help with communication

Question 5

stability

Answer 5

muscles maintain posture by preventing unwanted movement. some are called antigravity muscles because most times they resist pull of gravity and prevent slumping. many muscles stabilise joints by maintaining tension on tendons and bones

Question 6

control of body and openings of passages

Answer 6

muscles encircling mouth serve not only for speech but for intake and retention of food while chewing. in eyelid and pupil, they regulate admission of light to eye. internal muscular rings to control movement of food, bile, blood, and other materials within the body. muscles encircling urethra and anus control elimination of waste. some of these muscles are called sphincters

Question 7

heat production

Answer 7

skeletal muscles produce as much as 85% of ones body heat which is vital to functioning of enzymes and therefore all metabolism

Question 8

1st class lever

Answer 8

has pivot in the middle and one side has effort and other resistance eg see saw

Question 9

2nd class lever

Answer 9

has fulcrum at one end and resistance (load) in middle and effort and one end

Question 10

3rd class lever

Answer 10

fulcrum at one end, effort in the middle and resistance at the other end eg flexion at elbow

Question 11

what is mechanical advantage

Answer 11

MA is calculated from the length of the effort arm and divided by the length of the resistance arm
digastric muscle and others provide effort while tension in temporals muscle and other provide resistance

Question 12

what’s an example of 3rd class level

Answer 12

flexion at elbow

Question 13

what’s an example of a second class lever

Answer 13

mandible when jaw is forcibly open

Question 14

how do you calculate MA

Answer 14

LE/LR

Question 15

what is MA>1

Answer 15

produces more force but less distance/ speed than used

Question 16

what is MA<1

Answer 16

produces less force but more distance/ speed than used

Question 17

skeletal muscle

Answer 17

striated/ voluntary muscle
100-500 mid thick
3-30 cm long
multinucleate- derived from myoblasts

Question 18

what are myofilaments

Answer 18

thick - 15nm dia, myosin protein has head and tail
thin- 7nm dia; fibrous (F) actin protein made of globular (G) actin; G actin has binding sited for myosin heads; tropomyosin protein can block active sites; each tropomyosin has calcium binding troponin protein
elastic- 1nm connection / titan very springy

Question 19

what is a motorunit

Answer 19

a motor unit consists of one Moto neuron and all skeletal muscle fibres that it innervates
a motor unit - 1 nerve fibre and all myofibrils innervated by it can be inly a few muscles fibres (3-6) for fine control eg muscles of eye or 1000 fibres for grow control

Question 20

what are the types of connective tissue of muscle

Answer 20

• muscle fibre- muscle cell
• muscle fascicle- bundle of muscle fibres; seen as strand when muscle is cut
• endomysium- ct that surrounds each fibre; carries capillaries/ nerves’ chemical exchange during excitation
• perimysium- ct that surrounds each fasciae; carries larger blood vessel/ nerves and stretch receptors
• epimysium- fibrous sheath around entire muscle
• fascia- ct that surrounds and separates muscle

Question 21

what are the shapes of muscles

Answer 21

fusiform- biceps brachii
parallel- rectus abdominis
triangular- pectoralis major
unipennate- Palmer interosseous
bipennate- rectus femoris
 multipennate- deltoid
circular- orbicularis oculi