Muscles 2

Answer 2

Muscles mitochondria generates ATP from energy in glucose, free fatty acids floating in the blood, + glucose in blood to use O2.

When muscles don’t need energy - stored as glycogen
When it needs energy- glucose is broken off of glycogen + uses glucose for energy

Question 3

Myoglobin

Answer 3

Protein that’s similar to hemoglobin because they transfer O2 within muscle cells.
They make muscles red in appearance.
Brings O2 from the plasma membrane to the mitochondria.

Question 4

Anaerobic Respiration

Answer 4

not oxygen respiration burn glucose without using O2

Question 5

Glycolysis

Answer 5

The first stage of cellular respiration happening in the cytoplasm.
* Glucose → 2 Pyruvate + energy
* Faster and less efficient than cellular respiration

Question 6

What do we do with leftover pyruvate?

From glycolysis

Answer 6

1. Convert to lactic acid
2. Lactic acid is transported to the liver
3. Turned back into glucose using energy

Question 7

Order in which muscle uses various energy sources

Answer 7

1. Creatine phosphate
2. Anaerobic respiration = glycolysis
3. Aerobic respiration of glucose
4. Aerobic respiration of fatty acids for long-sustained contraction

Rest

Question 8

What happens when a muscle returns to a state of rest?

Answer 8

Reserves are restored of phosphocreatine, glycogen (to make glucose), and fatty acids.

Question 9

Reasons a muscle may fatigue

Answer 9

1. Run out of ATP to contract
   * Muscle will stop contracting before completely running out or else the cell would die
2. Ion imbalances
   * Ca++ coming out of sarcoplasmic reticulum
   * K+ in plasma membrane from muscle action potential
3. CNS can shut muscles down so it doesn’t get overused
4. Not from lactic acid build-up

Question 10

Muscle Fiber
Types

Answer 10

1. Fast oxidative
2. Slow oxidative - Slow Twitch
3. Fast glycolytic fibers - Fast Twitch

Question 11

Fast Oxidative Fibers

Answer 11

Muscle fiber type that use an intermediate balance of glycolysis + aerobic cellular respiration.
* Intermediate in all ways
* Used for sustained actions (running, walking)

Has intermitate sized motor units

Question 12

Slow Oxidative Fibers

Answer 12

Slow Twitch Muscle Fibers
* Use mostly Aerobic respiration
* Slower + weaker contractions
* Take a long time to fatigue
* Used for long contractions (posture)
* Fine motor movements (hands)

Question 13

Fast Glycolytic Fibers

Answer 13

Fasty Twitch Muscle Fibers
* Use mostly glycolysis + anaerobic respiration
* Faster + stronger contractions
* Fatigue quickly
* For bursts of action (jumping)

Question 14

Physical attributes of slow oxidative fibers

Answer 14

Slow twitch fibers have:
* Lots of mitochondria
* Small / skinny in size for O2 diffusion into the cell
* Lots of blood vessels
* Darker in appearance from blood

Question 15

Physical attributes of fast glycolytic fibers

Answer 15

Fasty twitch fibers have:
* Low mitochondrial count
* Large / wide in diameter
* Fewer blood vessels
* Lighter in appearance

Question 16

Slow Motor Unit
Attributes

Answer 16

• Small in size
• Controls only a few slow oxidative fibers at a time
• Neurons are small
• Responsible for fine (small) movements

Question 17

Large Motor Unit
Attributes

Answer 17

• Large in size
• Controls many fast glycolytic fibers at a time
• Neurons are large for faster responses
• Responsible for big course movements

Question 18

Smooth Muscle
Locations

Answer 18

Lining: Digestive, respiratory, reproductive, and urinary tracts and blood vessels
Inside the eye
Inside skin (arrector pilli)

Question 19

Smooth Muscle
Attributes

Answer 19

• Cells are tapered at ends
• Very a lot in size
• No epimysium
• Do have endomysium around cells
• Involuntary
• Some can be controlled by the hypothalamus (unconscious CNS)
• Some autorythmic
• Some respond to stimuli from things other than CNS

Question 20

What are the layers of smooth muscle in hallow organs?

Answer 20

1. Circular layer - closer to lumen
2. Longitudinal layer - outside circular

Question 21

Circular Layer

Answer 21

Layer of smooth muscle in hallow organs that’s closer to the lumen (Deeper).
Goes in circles around the lumen.
Contraction narrows the lumen.
Blood vessels located in this layer.

Question 22

Longitudinal Layer

Answer 22

Layer of smooth muscle in hallow organs that runs along the length of the organ outside of the circular layer.
Contraction makes the organ shorter.

Question 23

Smooth muscle contractions:

How it differes from striated muscle contractions

Answer 23

Take longer to contract or relax than skeletal or cardiac muscle.
Fatigues very slowly, maybe never.
Changes in length are greater than skeletal or cardiac.

Question 24

How does smooth muscle contract?

Answer 24

By myosin pulling on actin in dense bodies.
When myosin pulls on actin → dense bodies are pulled closer together
Contractions pinch + twist cells

Dense Bodies: protein complexes

Question 25

Smooth Muscle Contraction Process

Answer 25

1. Ca++ flows into the cytoplasm
2. Ca++ activates calmodulin (protein that acts like troponin
3. Calmodulin activates Myosin Light Chain Kinase (MLCK)
4. MLCK adds a phosphate to myosin for activation
5. Myosin grabs Actin + pulls
6. Relaxation

Question 26

Calmodulin

Answer 26

A protein in smooth muscle that’s activated by Ca++.

The troponin of smooth muscle

Question 27

Myosin Light Chain Kinase (MLCK)

Answer 27

Protein in smooth muscle activated by calmodulin

Question 28

Smooth muscle relaxation process

Answer 28

1. Ca++ levels drop
2. Calmodulin is deactivated
3. Calmodulin no longer activates Myosin Light Chain Kinase
4. Myosin Light Chain Phosphatase (MLCP)- Removes phosphate from myosin
5. Myosin no longer contracts
6. Cell relaxes

Question 29

In what ways can Ca++ flow into smooth muscle’s cytoplasm?

Answer 29

1. Through the sarcoplasmic reticulum (like striated)
2. From the extracellular fluid through Ca++ protein channels of the plasma membrane