Muscle Tissue Part 2

Front 1

what 4 factors determine the strength of muscle contraction?

Back 1

1. metabolic condition (fatigue)

2. amount of load

3. recruitment of motor units

4. initial length of mm fibers

Front 2

tension of a muscle is determined by __________.

Back 2

extend of overlap of actin-myosin myofilament (length/tension)

Front 3

what are the 2 types of mm fibers?

Back 3

1. fast-twitch

2. slow-twitch

Front 4

differences between fast-twitch & slow-twitch?

Back 4

fast-twitch: fibers stimulated by large/fast conduction of nerves (exercise), energy from stored glycogen (anaerobic respiration),disadvantage = easily fatigue, white appearance, used for explosive HIT

slow-twitch: fibers stimulated by tiny/slow conduction nerves, energy from fats & carbs (aerobic metabol.), disadvantage = can't be used for HIT, red appearance, higher resistance to fatigue (mms that control posture)

Front 5

what's strength training?

Back 5

increases # of myofilaments in each mm fiber, increases strength mm can generate, increases mm mass (muscle fiber is unchanged)

Front 6

what's endurance training?

Back 6

doesn't increase mm mass, increases number of BV (delivery of more O2 &glucose), increases # of mitochondria (ATP delivery) to mm

Front 7

What's smooth mm?

Back 7

cells: spindle shaped

arrangement: circular layers around hollow organs & in BVs, non-striated

not arranged into sarcomeres = can contract when cells have been greatly stretched

SR: loosely arranged w/in cells

no t-tubules/ no dense bodies (z discs)

Front 8

what are 2 types of smooth mm?

Back 8

single unit (unitary/visceral): in GI/GU tract & uterus; gap junctions present (cause contractions)

**GI tract has pacemaker

- function = syncytium

multi-unit: in iris, ciliary lens, arector pili, vas deferens; no gapjunctions

Front 9

the Ca-Calmodulin complex activates __________.

Back 9

myosin light chain kinase > exposes binding sites for actin > actin & myosin form crossbridges > mm contraction

Front 10

relaxation of mm tissue in terms of calcium & Ca-Calmodulin?

Back 10

calcium pumped back into SR. Ca-calmodulin isn't formed SO mm contraction doesn't occur

Front 11

how does sympathetic stimulus effect smooth mm?

Back 11

fight or flight > pupilary dilation, dilation of coronary vessels

** decreased intestinal motility & bronchial dilation

Front 12

how does parasympathetic stimulus effect smooth mm?

Back 12

rest & digest > opposite of fight or flight

**undilated pupils, undilated coronary vessels

increased intestinal motility & bronchial dilation

Front 13

what is Chaga's disease?

Back 13

parasitic infection (trypanasoma cruzi) that causes damage to mm in GI tract **esophagus

- difficulty swallowing, chest pain, drequent pneumonia

Front 14

what is the structure of cardiac mm?

Back 14

cells interconnected through gap junctions & function in syncytium (smooth mm)

contains sarcomeres & striated (skeletal mm)

Front 15

what regulates the contraction of cardiac tissue?

Back 15

autonomic nervous system

Front 16

what's chronotrophy? what's inotrophy?

Back 16

chronotrophy: rate of contraction

inotrophy: strength of contraction

- positive chronotropic/inotropic: binding epinephrine & norepinephrine to adrenergic receptors (sympathetic: fight/flight)

- neg. chronotropic/inotropic: binding of ACh to mucarininc receptors (parasympathetic: rest&digest)