b3.3 (muscle and motility)

Question 1

an organism that uses its own energy to move from place to place is motile. motile organisms: x4

Answer 1

are active feeders, searching for food
require higher amounts of nutrients
have higher metabolic rates
must search for mating partners

Question 2

an organism that can not direct its movement from place to place is sessile. sessile organisms: x3

Answer 2

are autotrophs or passive feeders
require fewer nutrients
have slower metabolic rates

Question 3

adaptations of marine mammals for swimming x5

Answer 3

streamlined body shape: long, narrow, tapered bodies reduce drag.

smooth skin (no body hair): minimizes friction with water.

forelimbs: modified into flippers for propulsion and steering.

tail (flukes): used for powerful up-and-down thrust.

pectoral fins: help with steering and balance.

Question 4

how does blubber serve as an adaptation in marine mammals? x3

Answer 4

insulates
provides buoyancy
stores energy for long migrations or deep dives

Question 5

how do specialized breathing techniques serve as an adaptation in marine mammals? x4

Answer 5

high myoglobin for oxygen storage
much more hemoglobin
control of breath and dive reflex for deep dives
blowhole that can be sealed to prevent water entry

Question 6

watch a video on how dolphins echolocate

Answer 6

-

Question 7

look at slide 19 b3.3

Answer 7

-

Question 8

what is an exoskeleton made of?

Answer 8

chitin

Question 9

what is an endoskeleton made of? x2

Answer 9

bone and cartilage

Question 10

skeletons can be compared to what? what does each aspect of this structure correlate to the parts of the skeleton

Answer 10

a lever

lever = the skeleton
fulcrum = a joint
effort = the muscles that pull on the bone at the insertion point
load = the mass being moved (usually body’s mass)

Question 11

first class lever structure & example in the body

Answer 11

fulcrum placed between the load and the effort (i.e. seesaw)

contractions of the muscle in the neck pull on the skull, causing the atlanto-occipital joint to pivot. the face rises.

Question 12

second class lever structure & example in the body

Answer 12

load between the effort and the fulcrum (i.e. wheelbarrow)

contractions of the calf muscle in the leg pull on the heel, causing the metatarsophalangeal joint to pivot. the foot rises.

Question 13

third class lever structure & example in the body

Answer 13

effort placed between the load and the fulcrum (i.e. hammer)

contractions of the bicep muscle in the arm pull on the radius, causing the elbow joint to pivot. the hand rises.

Question 14

define joint

Answer 14

the site of the junction of two or more bones of the body

Question 15

3 classifications of joints

Answer 15

immovable, fibrous
slightly movable, cartilaginous
freely movable, synovial

Question 16

synovial joints defining characteristic

Answer 16

a fluid-filled space between smooth cartilage pads at the end of articulating bones

Question 17

parts of synovial joints x7

Answer 17

joint capsule
bones
cartilage
synovial fluid
ligaments
muscles
tendons

Question 18

define joint capsule

Answer 18

a flexible, fibrous tissue that surrounds a joint and provides protection and stability

Question 19

what does cartilage in a joint do?

Answer 19

covers the bone at the joint to prevent friction and absorb shock

Question 20

example types of synovial joints, structure, range of motion, & examples x2

Answer 20

hinge joints (convex surface fitting into a concave surface) (limited range of motion) (elbow, knee, finger)

ball & socket joints (rounded “ball” fitting into a cup-like “socket”) (wide range of motion) (hip, shoulder)

Question 21

the hip joint is a ball-and-socket joint that connects X to X

Answer 21

the femur to the pelvis

Question 22

how to measure range of motion x2

Answer 22

goniometer (a tool with two arms that are hinged together and positioned at a joint to measure the angle)

analysis of images (using computer programs or phone applications that measure angles)

Question 23

directions of movement with definitions (& how they can be seen in relation to the hip) x6

Answer 23

flexion: bending a joint, decreasing the angle of the bones at these joints (brings leg up towards the chest)

extension: straightening a joint, increasing the angle between the bones at these joints (brings the leg backwards)

abduction: movement of a limb away from the center of your body (brings the leg outwards)

adduction: movement of a limb towards the center of the body (brings the leg inwards)

medial rotation: rotating limb toward the center of the body (brings the leg inwards)

lateral rotation: rotating a limb away from the center of the body (brings the leg outwards)

Question 24

define antagonist muscle pairs

Answer 24

muscle pairs that work together to facilitate motion through controlling “opposite” movements (when one contracts, the other relaxes)

Question 25

examples of antagonist muscle pairs x3

Answer 25

bicep & tricep glute & hip flexor quad & hamstring

Question 26

antagonist muscle pairs involved in running (mid stance vs toe off)

Answer 26

mid stance: contracting glute to pull foot up, relaxing hip flexor (for extension) toe off: relaxing glute to enable hip flexion. contracting hip flexor to drive knee up.

Question 27

what do the external and internal intercostal muscles each do for breathing?

Answer 27

external intercostal muscles: (located on the outside of the rib cage) responsible for elevating the ribs during inhalation, which increases the volume of the thoracic cavity and allows air to enter the lungs internal intercostal muscles: (located on the inside of the rib cage) responsible for depressing the ribs during exhalation, which decreases the volume of the thoracic cavity and helps push air out of the lungs

Question 28

motor neurons branch at the end of the axon. what does each branch do?

Answer 28

stimulates a different muscle fibre

Question 29

when do skeletal muscles contract?

Answer 29

when stimulated by a motor neuron

Question 30

define motor unit

Answer 30

the single motor neuron together with all of the muscle fibres it stimulates

Question 31

define neuromuscular junction

Answer 31

the synapse between a motor neuron and a muscle

Question 32

when an action potential reaches the synaptic terminal of the motor neuron, it causes the release of what? how does this cause a muscle contraction?

Answer 32

the neurotransmitter acetylcholine into the synaptic cleft acetylcholine triggers the opening of ion channels. Na+ ions flow into the muscle fibre and cause it to contract

Question 33

what is sarcolemma

Answer 33

cell membrane specific to muscle cells

Question 34

each myofibril consists of a series of repeated sarcomeres linked end to end (see slides 48 & 50). the sarcomeres are what give muscles their striated appearance. what is the structure of a sarcomere x5 components

Answer 34

Z lines actin (thin filament) (may also be proteins tropomyosin or troponin) myosin (thick filament) M line (in middle) titin (elastic filament)

Question 35

what are z-lines? what do they do?

Answer 35

protein structures that anchor the actin filaments and define the boundaries of the sarcomere

Question 36

what is titin? what do they do?

Answer 36

spring like protein that anchors myosin to the Z-line and recoils the sarcomere after contraction

Question 37

when a muscle contracts, the sarcomeres get shorter. how is this performed?

Answer 37

thin filaments (actin) are pulled inwards to slide over the thick filaments (myosin) when the thin filament moves, the Z-lines of the sarcomere are pulled closer together, shortening the sarcomere and contracting the muscle

Question 38

steps of sliding filament theory x10 (after, look at 53 to 62 for step details)

Answer 38

Muscle at rest Arrival of action potential triggers release of achetolychine at the neuromuscular junction Action potential travels along the sarcolemma membrane and down T-tubules Release of Ca2+ ions from the sarcoplasmic reticulum Ca2+ binds to troponin, causing tropomyosin to move off of myosin binding sites on actin Myosin heads bind to actin, forming a crossbridge Myosin head flexes, moving the actin filaments inwards, shortening the sarcomere ATP attaches to the myosin heads, breaking the crossbridge Steps 6-8 repeat in a cross-bridge cycle Contraction ends when Ca2+ is pumped back into the sarcoplasmic reticulum

Question 39

titin's role in muscle relaxation

Answer 39

provides passive elasticity that helps muscles return to their resting length during relaxation

Question 40

antagonistic muscle role in muscle relaxation

Answer 40

skeletal muscles work in pairs where one muscle contracts to produce a movement, while the other relaxes to allow that movement to occur. when on muscle contracts, the antagonistic muscle will relax

Question 41

3 primary functions of titin

Answer 41

provides sarcomere stability by anchoring the myosin filament to the Z-line helps sarcomeres recoil after contraction when stretched, titin generates power for rapid motion when it recoils

Question 42

define elastic potential energy. where is it typically stored in muscle cells?

Answer 42

the energy stored in a spring when it is stretched or compressed stored in protein titin

Question 43

why are antagonistic muscle pairs necessary?

Answer 43

skeletal muscles can only exert force on the bone when they contract. a muscle cannot supply the energy it needs to lengthen itself (the energy for lengthening of a muscle is provided by the contraction of the antagonistic muscle)