lec 8- Muscle and bones

Question 1

what are the two types of movement?

Answer 1

-Movement of entire animal relative to environment
-Movement of one part of the animals body relative to entire body

Question 2

what does movement allow an animal to do?

Answer 2

seek food, water, shelter, mates, and avoid predators

Question 3

what are voluntary muscles?

Answer 3

muscles that can respond to conscious thought and are stimulated by neurons in somatic division

Question 4

what are involuntary muscles?

Answer 4

muscles that contract in response to unconscious electrical activity and are stimulated by neurons in the autonomic division

Question 5

what are smooth muscle characteristics and what does it do?

Answer 5

are unbranched, tapered at each end, and often organized in thin sheets, lack sarcomeres, unstriated and involuntary. Essential to lungs, blood vessels, digestive system, urinary bladder, and reproductive system

Question 6

what neurotransmitter stimulates stomach contractions?

Answer 6

Acetylcholine

Question 7

which neurotransmitters inhibit stomach contractions?

Answer 7

Sympathetic neurons release norepinephrine and glands release epinephrine which inhibit contractions

Question 8

what are cardiac muscle characteristics and what does it do?

Answer 8

Contain sarcomeres and are striated, have branched structure and are directly connected end to end by intercalated discs which are important for heartbeat coordination and it is involuntary. Make up the walls of the heart and is responsible for pumping blood throughout the body

Question 9

what acts as glue to stick intercalated discs together?

Answer 9

Desmosomes

Question 10

what lets electrical signals to pass through the intercalated discs

Answer 10

Gap junctions

Question 11

what do parasympathetic neurons secrete to slow down the heartbeat?

Answer 11

acetylcholine

Question 12

what do sympathetic neurons secrete to speed up the heartbeat?

Answer 12

norepinepherine and epinephrine

Question 13

what is a cardiomyocyte?

Answer 13

a contractible heart cell

Question 14

what happens during the plateau phase in a cardiomyocyte?

Answer 14

calcium influx, calcium channel opens allowing complete contraction

Question 15

what are skeletal muscle characteristics and what does it do?

Answer 15

Exceptionally long, unbranched, multinucleate muscle fibres, voluntary, striated, result from the fusion of multiple cells. Allows movement of an organism

Question 16

what are myofibrils made of?

Answer 16

many sarcomeres

Question 17

do skeletal muscles exert a force?

Answer 17

yes, that is how we move

Question 18

what are skeletal muscles stimulated by?

Answer 18

somatic motor neurons, damage to them results in paralysis

Question 19

what are the three types of skeletal fibres?

Answer 19

Slow muscle fibres, fast muscle fibres, and intermediate muscle fibres

Question 20

explain slow, fast, and intermediate muscle fibres

Answer 20

-Slow muscle fibres-
Appear red due to presence of iron bound with oxygen in myoglobin which stores oxygen, contract slowly due to myosin hydrolyzing ATP at a slow rate and fatigue slowly due to big stream of ATP from mitochondria via aerobic respiration
-Fast muscle fibres-
Appear white due to low myoglobin, contract rapidly due to myosin hydrolyzes ATP at a fast rate, fatigue fast because main source of ATP is glycolysis
-Intermediate muscle fibres-
Appear pink or red, contractile properties vary but intermediate between slow and fast fibres, obtain ATP from glycolysis and aerobic respiration

Question 21

can humans increase density of mitochondria and myoglobin enabling increased performance?

Answer 21

yes, but not slow or fast muscle fibres

Question 22

what are the two types of muscle arrangements and what do they do?

Answer 22

Parallel- small force, large length change
Pennate- large force, small length change

Question 23

what are the three types of skeletal systems and what do they do?

Answer 23

Hydrostatic system- use hydrostatic pressure of enclosed body fluids to support body
Exoskeletons- have rigid structures on the outside of body, apodemes are the ingrowth where muscles attach
Endoskeletons- have rigid structures inside the body, change shape by changing joint angles

Question 24

what is cartilage?

Answer 24

cells scattered in a gelatinous matrix

Question 25

what is a ligament?

Answer 25

bands of fibrous tissue that connect bones to bones

Question 26

what is a tendon?

Answer 26

fibrous connective tissue that connects bone to skeletal muscle

Question 27

what are osteoblasts and osteoclasts and what they do?

Answer 27

Osteoblasts- secrete extracellular matrix that builds bone
Osteoclasts- reabsorb bone by secreting acid

Question 28

what are osteogenic cells and osteocytes and what do they do?

Answer 28

Osteogenic cells- develop into osteoblasts
Osteocytes- secreted matrix of osteoblast calcifies and becomes osteocytes after conformational change, most common bone cell

Question 29

what is osteoporosis?

Answer 29

Osteoporosis is a disease that makes bones brittle