KIN 413 FINALS

What are *Receptors (in CNS)*?

specialized tissues performing a specific sensory role for the nervous system

*Feedback*

What is Proprioception?

The sense of self-movement and body position

Proprioception allows for awareness of what three things?

(1) Muscle length
(2) Musculo-skeletal interface (joint angle change)
(3) Speed of movement

What are Muscle Spindles?

Stretch receptors (made up of intrafusal fibers) within muscle that primarily detects changes in muscle length

What does stretched intrafusal fibers stimulate?

gamma motor neurons

Muscle Spindle Feedback

When muscle spindles are rapidly stressed, the sensory feedback causes the CNS to stimulate alpha motor nerves and cause muscle contraction.

Draw/describe the two types of intrafusal fibers.

The Gamma Systems consists of what?

Muscle spindles

What are the two types of intrafusal fibers?

(1) Nuclear bag
(2) Nuclear chain

What three things determine Intrafusal fiber type?

(1) Length/diameter
(bag > chain)
(2) Central nuclei
(bag > chain)
(3) Innervation
(bag 1:1 < Chain 1:5)

What does the Nuclear Bag monitor?

rate and degree of stretch

What does the Nuclear Chain monitor?

Degree of stretch

How many types of afferent nerves are in the gamma system?

2

What innervates intrafusal fibers?

(1) Sensory nerves
(afferent fibers)
(2)Motor nerves
(efferent fibers)

How many types of gamma efferent nerves are in the gamma system?

1

What are the Two Types of Afferent nerves?

(1) Annulospiral ending
(2) Flower spray ending

Where are annulospiral endings located?

On the primary endings (central part) of both the nuclear bag and nuclear chain

Where are flower spray endings located?

On the second ending (right end part) of the nuclear chain

What two things stimulates afferents?

(1) Muscle length
(2) Gamma efferents

Where do Gamma Efferents innervate?

On the plate/trail endings (left end part) of the nuclear bag/ nuclear chain. They allow contraction of the intrafusal fibers and increase their sensitivity to stretch.

Do gamma efferents have a slower or faster conduction velocity than alpha motor neurons?

Slower

When do gamma efferents sense movement?

When there is a change of muscle length (their contractile ends are stimulated to contract in order to compensate the change in muscle length)

What is the gamma loop?

it is a feedback loop in the nervous system that regulates the level of tension in muscles

What is co-activation?

When both alpha and gamma motoneurons are stimulated and the gamma loop is initiated

What does the Gamma loop help accomplish?

the Inhibition of antagonistic (opposing) muscle actions

What is gamma bias?

gamma motor neurons' consistent level of activity.


Gamma motor neurons have a lower threshold than alpha motor neurons causing them to fire more often. This creates a situation with relatively few alpha motor neurons firing but some gamma motor neurons constantly firing in conditions where muscle stretch or force is not occurring.

What is precision control of Gamma Bias?

muscle contraction is maintained at varying levels of force

In Gamma Bias, when extrafusal fibers are at a prefered length what occurs?

(1) minimal spindle firing
(2) unconscious control (convergence = less jerky movement)

Where is the Golgi tendon organ located?

near the junction of the muscle and tendon fibers

What is the golgi tendon organ?

A proprioceptor encapsulated in tendon fibers that senses the amount of tension during muscle contraction (to relay to CNS)

When the Golgi organs sense that tension is too high, what does the CNS do?

Sends an inhibitory signal to the muscle to reduce muscle contraction (Autogenic Inhibition)

What is autogenic inhibition?

a reduction in excitability of a contracting or stretched muscle

What effect goes strength training have on the Golgi tendon organ?

reduced activity

Where do Joint Receptors relay messages?

sensory cortex (directly)

What two things do joint receptors relay?

(1) Movement of all joints coordinated through cortex
(2) Conscious body position awareness

What three things do cutaneous Receptors sense?

(1) Pressure
(2) Temperature
(3) Tissue Damage

Where do cutaneous receptors relay messages?

Sensory cortex

What is the Labyrinth of the Ear?

Sensory of structures that help with body position awareness

To what movement type does the semicircular canals respond?

Angular movement

To what movement type does the utricles (saccule) respond?

linear/gravitational movement

Why are the utricles (saccule) important?

They help maintain the body's center of gravity

The Tonic Neck Reflex is a remnant from what?

infancy

What does dorsiflexion of the upper cervical neck facilitate?

extension of limbs (tilting your head backwards)

What does ventriflexion of the upper cervical neck facilitate?

flexion of limbs (tilting forwards)

What is a reflex arc?

basic unit of integrated activity

The Reflex Arc consists of what five things?

(1) Sense organ - receptor
(2) Afferent neuron
(3) One or more synapses in a central integrating station (except monosynaptic reflex) AKA interneurons
(4) Efferent neuron
(5) Effector organ

What is a polysynaptic reflex?

A reflex action that involves an electrical impulse being transferred from a sensory neuron to a motor neuron via at least one connecting neuron (interneuron) in the spinal cord.

What are two examples of Polysnapatic Reflexes?

(1) Extensor Thrust Reflex
(2) Crossed Extensor Reflex

What is the Extensor Thrust Reflex?

a reflex extension of the leg caused by applying a stimulus to the sole of the foot. The reflex normally occurs each time a person takes a step in walking or running, signaling a need for body support and providing the thrust for taking the next step

Knee extensors stimulated to contract upon stimulation of sole of foot (as in landing from a jump)

What is the crossed extensor reflex?

(1) Ipsilateral knee flexion (avoidance)
(2) Contralateral knee extension (balance)

What are proprioceptive reflexes during skilled movements?

(1) Perform detailed action with minimal conscious awareness
(2) Neuromuscular patterning
(3) Early errors are attributed to interference between consious direction of cortex v. smooth functioning action of subcortical levels

What is Neuromuscular patterning?

grouping simple movements into complex patterns

What happens in sensory motor integration?

A sensory stimulus is transmitted to the brain (CNS) via sensory neurons where it is interpreted and sent as a motor response via motor neurons. The motor impulse then reaches muscle and response is initiated.

Describe the pathway from a stimulus to a response.

(1) sensory signal is sent directly to the spinal column
(2) crosses interneurons, which initate an immediate response
(3) Sensory info is sent to CNS

What is the equation for Body Composition?

Total Body Mass (TBM) = Fat Mass + Lean Body Mass

(includes all nonfat tissues)

What are the six functions of fat?

(1) Insulation/cushioning
(2) Stored energy (greatest capacity)
(3) Structural (cell membrane)
(4) Involved in nerve conduction (myelin sheath)
(5) Absorption of fat soluble vitamins (critical A,D, E, K)
(6) Backbone for steroid hormones (estrogen, cortisol, etc.)

What is Hydrostatic Weighing?

Constituents are separated based on DENSITY with respect to specific gravity of water --> essentially something is placed underwater and the water that is displaced equals the volume of the object

What is Specific gravity (density) of water?

Related to temperature
Near 1.0

At what temperature is water densest?

4 degrees celsius (best for drinking)

What is the Density of Fat Constituents?

~0.9

What is the Density of lean body constituents?

~ >1.0

What is plethysmography?

The scientific study of body composition based on displacement of substances (water, air).

What is Anthropometry?

the scientific study of the measurements and proportions of the human body. (may use: skin folds, girth, weight, height)

How is body mass index (BMI) measured?

weight/height^2 (kg/m^2)

According to BMI, those who work out may be over weight. What is needed to accurately determine BMI?

Waist circumference

What are the two body shapes?

(1) Android = Apple
(2) Gynoid = Pear
think OB-gyn - dealing with the lower half of the body

What can abdominal obesity can lead to?

(1) High plasma insulin
(2) High triglyceride lipase activity
(3) Low HDL2 (increases risk for heart disease)

What is Bioelectrical Analysis (BIA)?

A method for estimating body composition that uses a small electrical charge to measure resistance (ohms)

Is lean (nonfat) tissue a good electrical conductor?

Yes

How does nonfat tissue effect resistance?

cause an decrease in resistance

Is fat issue a good conductor? Insulator?

Poor conductor, Good Insulator

How does fat tissue effect resistance?

cause an increase in resistance

What are potential problems with BIA?

(1) Prediction Equation
Fat people < value % fat
Thin people > value % fat
(2) Dehydration effects results
diuretics, exercise, heat

What is Infrared Interactance?

Method of assessing body composition in which an IR beam goes into the tissues (both fat and nonfat)

(tissues have different refractive reflective properties)

What is the problem with Infrared Interactance?

Prediction Equation: only uses one site compared to >2 in original research

What is the 4-Compartment Model?

A model factoring in body mass (BM), body volume (BV), total body weight (TBW), and body mass composition (BMC)

What are the four things the 4-Comparentment Model measures?

1. Water
2. Protein
3. Bone minerals
4. Fat
(how I remember it: Water + PBF!)

What is Dual-energy X-ray absorptiometry (DEXA)?

An imaging test that measures bone density by passing x-rays with two different energy levels through the bone. It is used to diagnose osteoporosis

(current benchmark used to compare methods)

Describe the Fat Burning vs. Training Zones (60% HR vs. 85% HR for 30 minutes).

Percent fat used is greater for what type of exercise?

Low-intensity exercise, but total amount is similar

The total calorie expended is greater for what type of exercise? This leads to what?

High-Intensity exercise

Leads to better long-term management of weight

What will HIIT work accomplish?

(1) Greater improvements in aerobic fitness
(2) reduction in cardiovascular disease
(3) Improved sense of vigor

To maximize HIIT workouts, what should be done?

Increase workload

How do you calculate Temporal Summation?

(firing rate x EPSP mV) + (firing rate x IPSP mV) + (Resting Potential)

Temporal Summation example

EPSP 4x/sec (+15 mV) = + 60 mV/sec
IPSP2x/sec (-12 mV) = -24 mV/sec

= +36 mV/sec + -70 mV

(Generator Potential) -34 mV > -50mV (RMP)

Action potential is created!

How do you calculate Spacial Summation?

(times fired x EPSP mV) + (times fired x IPSP mV) + (Resting Potential)

Spatial Summation Example

Spatial Summation
3 EPSP x +5 mV = +15 mVo2
IPSP x -6 mV = - 12 mV
+ 3 mV -70 mV (Resting Pot.)
= -67 mVo

No action potential but this has become a facilitated nerve (generator potential is less negative than resting membrane potential)

How do you calculate how long it would take to reach threshold?

(firing rate x EPSP mV) + (times fired x IPSP mV)

How many times would that would have to be added to the resting potential to reach threshold?

What are three types of muscle tissue?

Cardiac, skeletal, smooth

What are elastic fibers?

Essential fibers for movement (fascia-related and other muscle proteins)

What are the contractile muscle proteins?

(1) Myosin (thick)
(2) Actin (thin)

What are the regulatory muscle proteins?

(1) Troponin
(2) Tropomyosin

What are the scaffold/spring muscle proteins?

(1) Titin
(2) Nebulin
(3) Obscurin

What is skeletal muscle composed of?

A composite of thousands of smaller contractile units that are grouped into smaller and smaller bundles

What is a sarcomere?

the smallest functional contractile unit in muscle fiber

What irrigates the muscle fiber system and sacromeres?

System of Tubules

Within muscle cells, where is calcium stored?

Within the sarcoplasmic reticulum/terminal cisternae

How does a muscle perform work?

It shortens

How does shortening of muscle create movement?

Pulls on tendon attached to bone

What is the sliding filament theory?

The theory which states that the sliding of actin past myosin generates muscle tension