Week 14

Question 1

What feedback loop controls blood pressure?

Answer 1

Negative

Question 2

A decrease in arterial blood pressure is detected where?

Answer 2

Stretch receptors in the neck blood vessels

Question 3

A decrease in arterial blood pressure causes what in baroreceptor firing?

Answer 3

Decrease in baroreceptor firing

Question 4

What effect does a decrease in baroreceptor firing have on the sympathetic?

Answer 4

Increase in systemic vascular resistance, so increases in cardiac output. Blood pressure is raised.

Question 5

What effect does a decrease in baroreceptor firing have on the parasympathetic?

Answer 5

Decreased vagal output causes increases in cardiac output. Blood pressure is raised.

Question 6

What’s the difference between somatic and autonomic nervous system?

Answer 6

Somatic= voluntary
Autonomic=cardiac, smooth, involuntary

Question 7

afferent vs efferent

Answer 7

afferent= carries sensory info to CNS
efferent= carries motor commands to muscles

Question 8

What is the most common state of reflexes?

Answer 8

Inhibition

Question 9

What is the sympathetic division of the spine?

Answer 9

thoraco-lumbar

Question 10

What is the parasympathetic division of the spine?

Answer 10

cranio-sacaral

Question 11

what does it mean when we say that symp and parasymp have tonic activity?

Answer 11

They have background activity, turns up or down. Not on/off

Question 12

What are the three main differences between Parasympathetic and Sympathetic nervous systems?

Answer 12

1. anatomical organisation
2. physiological effects
3. pharmacological properties

Question 13

How is the autonomic response able to produce such diverse effects?

Answer 13

Receptor population and type

Different receptors invoke different G proteins/ 2nd messengers
Giving specific effects

Question 14

describe the sympathetic impact on arterioles?

Answer 14

1.Increased sympathetic activity
2. relaxation via beta receptors in heart, lungs and brain
3.more blood flow to those
4.Strong constrictrion via alpha receptors in skin, kidneys

Question 15

What types of muscle are striated?

Answer 15

skeletal, cardiac

Question 16

What types of muscle are non striated?

Answer 16

smooth

Question 17

What types of muscle are voluntary?

Answer 17

skeletal

Question 18

What types of muscle are involuntary?

Answer 18

cardiac and smooth

Question 19

What percentage of an adult’s body mass is taken up by muscle?

Answer 19

50%

Question 20

In a Muscle there are bundles of what?

Answer 20

Muscle fibres

Question 21

What are bundles of muscle fibres wrapped in?

Answer 21

Perimysium

Question 22

What does each muscle fibre contain?

Answer 22

Myofibrils and mitochondria
wrapped in sarcoplasmic reticulum then sarcolemma

Question 23

What is each myofibril made up of?

Answer 23

Actin and myosin in a sarcomere
Z discs

Question 24

What are Z discs?

Answer 24

The edges of sarcomere

Question 25

What two types of actin are there?

Answer 25

Globular actin= beads on a necklace F actin=string

Question 26

Describe the structure of actin

Answer 26

G actin and F actin strands in a double helix Tropomyosin is the thread down the middle of the double helix Troponin binds actin to tropomyosin

Question 27

How does troponin initiate the muscle contraction process?

Answer 27

troponin binds to Ca2+ Triggering a shift in tropomyosin Exposing myosin binding sites on actin Myosin and actin bind Ca2+ unbinds Myosin and actin ubind repeat

Question 28

What three things does force of muscle contraction rely on

Answer 28

1. Recruitment (No of motor units activated) 2. rate modulation (action potential firing rate) 3. Length-Tension relationship (no cross bridges formed)

Question 29

isotonic vs isometric muscle contractions

Answer 29

isotonic= moving a weight, muscle shortens isometric= muscle develops tension without length change

Question 30

Give some examples of where you could find smooth muscle?

Answer 30

Bladder, GI tract, uterus, blood vessels,eye

Question 31

What is piloerection? And what kind of muscle performs this?

Answer 31

Hairs stand up Smooth muscle under skin controls this

Question 32

Describe the contractile proteins in smooth muscle

Answer 32

Contraction is squishy/ 3D Myofilaments and intermediate filaments are the 'fishing net' Dense bodies hold fishing net

Question 33

Describe the structure of Single unit smooth muscle

Answer 33

Gap junctions allows coordinated contractions

Question 34

Describe the structure of multi unit smooth muscle

Answer 34

Fibres contract independently

Question 35

What kind of activity would a single unit smooth muscle have?

Answer 35

Autonomic Bladder, uterus, GI Some have spontaneous activity/ muscles mostly contracted eg. sphincter

Question 36

What kind of activity would a multi unit smooth muscle have?

Answer 36

Autonomic but never spontaneous eg. ciliary, piloerector

Question 37

Why does smooth muscle require an extra step of activation compared to striated muscle?

Answer 37

1. sarcoplasmic reticulum not as developed 2. no T tubule 3. Myosin Light chain kinase

Question 38

Describe how Myosin Light chain kinases function?

Answer 38

1.Calmodulin binds to Ca2+, thsi complex binds to MLCK to activate it 2. MLCK use ATP to phosphorylate myosin cross bridges

Question 39

Is cardiac muscle straited or non striated?

Answer 39

Striated

Question 40

How many nuclei per cell do cardiac muscle have?

Answer 40

Single nucleus per cell

Question 41

How are cardiac cells connected to one another?

Answer 41

Connected via intercalated disks Desmosomes 'popper' together cells

Question 42

What controls the speed of contraction of cardiac cells?

Answer 42

ANS

Question 43

How are Ryanodine receptors involved in the contraction of cardiac muscle cells?

Answer 43

Incoming Ca2+ binds to Ryanodine receptors (RYR2) Causing more Ca2+ to release form SR to cytosol (positive feedback loop)

Question 44

What is the name of foxglove?

Answer 44

Digitalis Purpurae

Question 45

How did Digitalis Purpurae help to treat dropsy?

Answer 45

1. Source of digotoxin (cardiac glycoside, +ve ionotropic) 2. inhibits Na+/K+ ATPase pump 3. Na+ builds up in the cell 4.Na+/Ca2+ exchange is reduced 5. Ca2+ build up 6. increased strength of cardiac contraction