Unit 9 Musculoskeletal Pt. 2

Question 1

Neural reflex pathways can be classified in different ways: Describe the efferent division the controls the effector. (1st) (What do somatic motor neurons control and Autonomic neurons control)

Answer 1

A) somatic motor neurons control skeletal muscles

B) Autonomic neurons control smooth and cardiac muscle, glands, and adipose tissue

Question 2

Neural reflex pathways can be classified in different ways: Describe the integrating region within the CNS. (2nd) (Spinal and cranial reflex)

Answer 2

A) Spinal reflexes do not require input from the brain

B) Cranial reflexes are integrated within the brain

Question 3

Neural reflex pathways can be classified in different ways: Describe the time at which the reflex develops. (3rd)

Answer 3

A) Innate (inborn) reflexes that are genetically determined

B) Learned (condition) reflexes are acquired through experience

Question 4

Neural reflex pathways can be classified in different ways:Describe the number of neurons in the reflex pathway. (4th) (Monosynaptic and Polysynaptic)

Answer 4

A) Monosynaptic reflexes only have two neurons: one afferent and one efferent
{Only somatic motor can be monosynaptic} (Patellar tendon reflex)

B) Polysynaptic reflexes include one or more interneurons between the afferent and efferent neurons.
{Autonomic reflexes are polysynaptic} (Arm being pulled away from noxious stimulate, like a hot stove)

Question 5

In polysynaptic reflex, compare divergence and convergence.

Answer 5

Divergence of pathways allows a single stimulus to affect multiple targets

Convergence integrates the input from multiple sources to modify the response

Question 6

What are autonomic reflexes?

Answer 6

Known as visceral reflexes, often involve internal organs of the body. Some visceral reflexes such as urination and defecation are spinal reflexes that take place without input of brain, through excitatory or inhibitory signals

Question 7

Where are autonomic reflexes integrated in the brain? What are the functions?

Answer 7

Primarily in the hypothalamus, thalamus and brain stem

They coordinate body functions needed to maintain homeostasis, such as HR, BP breathing, eating, water balance and maintaining body temp.

Brain stem also contains integrating centers for autonomic reflexes such as vomiting, salivating, sneezing, swallowing, and gagging

Question 8

What is the limbic system in charge of?

Answer 8

The site of primitive drives such as sex, fear, rage, aggression, and hunger- has been call the “visceral brain” because it’s in charge of emotional driven reflexes
(Gut-feeling, and “butterfly’s in stomach”)

Question 9

What are the three proprioceptors found in the body?

Answer 9

Joint Receptors

Golgi Tendon organ

Muscle spindles

Question 10

Describe joint receptors (one of the proprioceptors)

Answer 10

Found in the capsules and ligaments around joints in the body. Sensory information is integrated primarily in the cerebellum. They are stimulated by mechanical distortion and changes in relative positioning of bones linked by flexible joints

Question 11

Describe Golgi Tendon Organ (GTO) (One of the proprioceptors)

Answer 11

Found at the junction of tendons and muscles fibers. GTOs respond primarily to muscle tension created during the isometric phase of contraction and are relatively insensitive to muscle stretch.
Muscle contraction pulls on collagen fibers within the GTO, pinching sensory endings of the afferent neurons and causing them to fire

Question 12

Describe muscle spindles. (One of the proprioceptors)

Answer 12

Stretch receptors the send information to the spinal cord and brain about muscle length and changes in muscle length. They are small, elongated structures scattered among and arranged parallel to the contractile extrafusal muscle fibers.

Each spindle consist of a connective tissue capsule that encloses the infrafusal fibers. The reflex pathway in which muscle stretch initiated a contraction response is known as a stretch reflex

Question 13

What are extrafusal fibers?

Answer 13

Fibers that build up, generate force and execute movement. Innervated by alpha motor neuron

Question 14

What are infrafusal fibers?

Answer 14

Fibers that are part of the muscle spindles- sensory receptors for muscle control and movements. Innervated by gamma motor neurons

Question 15

What is Alpha gamma coactivation?

Answer 15

Gamma motor neurons keep muscle spindles active no matter what the muscle length is. When alpha motor neurons fire, muscle shortens which releases tension on muscle spindle capsule. Gamma motor neurons then come in to active and shorten the spindle. This excitation of both gamma and alpha motor neurons at the same time is known as alpha gamma coactivation.

Question 16

How are stretch reflex and alpha gamma coactivation activated during plyometric exercise?

Answer 16

The stretch reflex will lead to strong contraction and the alpha-gamma activation helps the muscle spindles detect the stretch reflex otherwise, the muscle spindle intrafusal muscle would not detect the quick stretch without being taut or contracted as well as gamma neurons.

Question 17

How will a PNF quick stretch technique facilitate a muscle contraction?

Answer 17

Because it helps induce the alpha gamma coactivation that leads to extrafusal and intrafusal fibers to reinforce contraction and possibly make it stronger.

Question 18

Explain patellar tendon reflex.

Answer 18

It’s a monosynaptic reflex, a rubber hammer is hit below the knee cap, tendon pulls on bone of patella and contracts quad muscle attached to patella.

This contraction of quads while hamstrings relaxes causes the leg to kick out. When the knee goes back to flexion, it requires the hamstrings to contract and for the quads to relax

Question 19

Explain the cross extensor reflex.

Answer 19

(Stepping on a Lego) Divergence

A flexion reflex causes extension of the opposite limb, this contraction of reflexes with postural adjustments is essential for maintaining balance.

Flexors contract moving foot away from painful experience

Extensors contract as weight shifts to other leg

Question 20

What is reciprocal inhibition and what neurons are responsible for it?

Answer 20

Reciprocal inhibitions is when antagonists flexor muscles relaxes during the contraction of the agonist muscle. ( hamstring relaxes while quad contracts)

Somatic motor neurons are activated to contract quads

Inhibitory interneurons suppresses activity in somatic motor neurons controlling hamstring

Question 21

What are voluntary movements?

Answer 21

The most complex type of movement. It requires integration of the cerebral cortex and can be initiated without external stimuli. (Muscle memory). For example, riding a bike.

Question 22

What are Rhythmic movements?

Answer 22

It is a intermediate complex movement. A combination of reflex and voluntary movements. Initiated by input from the cerebral cortex. For example, walking or running.

Question 23

What are Feedforward reflexes?

Answer 23

The least complex type of movement. Allows the body to prepare for a voluntary movement and be used to create a smooth, continuous motion

Question 24

Where are Voluntary movements integrated from?

Answer 24

In the cerebral cortex

Question 25

Where are Rhythmic movements integrated from?

Answer 25

Integrated in the spinal cord with higher center input required.

Question 26

Where are Feedforward Reflexes integrated from?

Answer 26

Integrated at the level of the spinal cord or brain stem with higher center modulation.

Question 27

What is the role of the spinal cord in Neural control of movement?

Answer 27

Spinal reflexes; Locomotor pattern generators

Question 28

What is the role of the Brian Stem in Neural control of movement?

Answer 28

Posture; Hand and eye movements

Question 29

What is the role of the Motor areas of the Cerebral Cortex in Neural control of movement?

Answer 29

Planning and coordinating complex movement

Question 30

What is the role of the Cerebellum in Neural control of movement?

Answer 30

Monitors output signals from motor areas and adjust movement

Question 31

What is the role of the Thalamus is Neural control of movement?

Answer 31

Contains relay nuclei that modulate and pass messages to cerebral cortex

Question 32

What is the role of the Basal Ganglia is Neural Control of movement?

Answer 32

Motor Planning

Question 33

What is Parkinson’s Disease?

Answer 33

A progressive neurological disorder characterized by abnormal movements, speech difficulties, and cognitive changes.

Question 34

What are the signs and symptoms associated with in Parkinson’s Disease?

Answer 34

They are associated with loss of neurons in the basal ganglia that release the neurotransmitter dopamine.

Tremors in hands, arms and legs, particularly at rest

Shuffling gait

Lost facial expression

Depression, personality changes

Question 35

Where does ATP come from for muscle contraction?

Answer 35

-A small amount is in the muscle fiber when contraction begins.
-Phosphocreatine (PCr) transforms energy to ADP to ATP, which replenishes the muscle supply of ATP.

Question 36

What nutrients yield the most energy per gram when metabolized?

Answer 36

Carbohydrates (Glucose) and fatty acids.

Question 37

Explain excess-post exercise oxygen consumption.

Answer 37

Oxygen is being used to
-metabolize lactate,
-restore ATP and PCr,
-replenish the oxygen bound to myoglobin,
-and increase body temp. and circulating catecholamines

Question 38

What type of energy is used for endurance training?

Answer 38

Aerobic= Glucose + Fats and is supported for a long duration. For Example, a marathon runner.

Question 39

What type of energy is used for resistance training?

Answer 39

Anaerobic = Glucose - Faster ATP production but it is brief. For example, Sprinters or power lifters.

Question 40

Where does glucose for aerobic and anaerobic ATP production come from?

Answer 40

Three sources:
-Plasma glucose pool
-Intracellular stores of glycogen in muscles and liver
-“New” glucose made in the liver through gluconeogenosis

Question 41

What is the difference between Aerobic, Anaerobic, and Phosphocreatine metabolism?

Answer 41

Aerobic metabolism supports exercise for hours.

Anaerobic produces ATP 2.5 times faster than aerobic metabolism but can support only one minute of maximal exercise.

Phosphocreatine can sustain only 10 seconds of maximal exercise.

Question 42

What changes occur in mitochondria with exercise?

Answer 42

Oxygen is consumed during the oxidative phosphorylation in the mitochondria, as it combines with hydrogen to form water.

Also the definition of Oxygen consumption

Question 43

How is oxygen consumption related to exercise intensity?

Answer 43

A person’s maximal rate of oxygen (VO2 max) is an indicator of the ability to perform endurance exercise. The greater the VO2 max, the greater the person’s predicted ability to do work.

Question 44

What is the advantage of decreased insulin secretion during exercise?

Answer 44

Less insulin means that cells other than muscle fibers reduce their glucose uptake, sparing blood glucose for use by muscles.

Question 45

How is blood redistribution during exercise?

Answer 45

During exercise blood flow to tissues increases due to:
-Increased cardiac output
-Increased vasodilation in skeletal muscles arterioles
(Sympathetic signals cause vasoconstriction in peripheral tissues at the onset of exercise, but as muscles become active O2 decreases, while temperature and CO2 increases so it induces vasodilation).

Question 46

Explain the normal ranges in Systolic BP, Diastolic BP, and HR and ventilation during exercise.

Answer 46

As cardiac output increases significantly during exercise, BP increases whether peripheral resistance decreases (vasodilation) or increases (Vasoconstriction).

Ventilation rates jumps as soon as exercise begins

Question 47

How is heat lost form the body during exercise?

Answer 47

Most of the energy released during metabolism is released as heat. With continued exercise, heat production exceeds heat loss, and core body temp. rises, which result in sweating and increased cutaneous blood flow.

Question 48

How may exercise improve type 2 diabetes mellitus?

Answer 48

With exercise, skeletal muscle fibers up-regulate the number of GLUT4 glucose transporters and insulin receptors on their membrane. Due to this, the muscles dependence on insulin for glucose uptake decreases and helps correct the hyperglycemia of diabetes.