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Exercise Phys Exam #2
terms and concepts
51
Physiology
Undergraduate 4
10/21/2008

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Term
What are endocrine glands and what do they do?
Definition
glands that release hormones (chemical messengers)directly into the blood.
Term
What are hormones and what do they do?
Definition
Hormones are chemical messengers that alter the activity of tissues that possess receptors to which the hormone can bind
Term
What 4 things effect the plasma concentration of a hormone?
Definition
1) The rate of secretion of the hormone from the endocrine gland
2) The rate of metabolism or excretion of the hormone
3) The quantity of transport protein (for some hormones)
4) Changes in the plasma volume
Term
What determines the rate of hormone secretion?
Definition
dependent on the magnitude of the input and whether it is stimulatory or inhibitory in nature.
Term
What three things determine the magnitude of effect at the cellular level of a hormone?
Definition
1) The number of receptors (doors) on the cell
2) The concentration of the hormone
3) Affinity of the receptor for the hormone
Term
What are the three methods discussed by which hormones bring about a response within the cell?
Definition
1)Through altering membrane transport (Facilitated membrane transport)
2)By stimulating DNA to increase protein synthesis. (directly binding to DNA)
3)Using 2nd messenger systems
Term
Growth Hormone:
Definition
Secreted from the anterior pituitary gland
Release stimulated by: exercise, stress, and low plasma glucose
Functions: 1) essential for normal growth - Stimulates protein synthesis (amino acid uptake) and long bone growth
2)Increases during exercise - mobilizes fatty acids from adipose tissue and aids in the maintenance of blood glucose(gluconeogenesis)
Term
Epinephrine/Norepinephrine:
Definition
Secreted by the adrenal medulla
80% Epinephrine, 20% Norepinephrine
Release stimulated by: High-intensity and long duration exercise, stress (fight or flight)
Functions: Increases Heart Rate, glycogenolysis, lypolysis
Term
Cortisol:
Definition
Secreted by the adrenal cortex
Release stimulated by: exercise, long term fasting, and stress
Functions: 1)Promotes free fatty acid use, blocks glucose entry into tissues
2)Stimulates glucose synthesis (liver)
3)Promotes protein breakdown for gluconeogenesis and tissue repair
Term
Testosterone:
Definition
Secreted by the testes
Release stimulated by: intense or long duration exercise
Functions: 1)Anabolic steroid - promotes tissue(muscle) building and performance enhancement
2)Androgenic steroid - promotes masculine characteristics
Term
What are the effects of an increase/decrease in hormone concentration seen with exercise? Why is this necessary?
Definition
?
Term
Insulin:
Definition
Secreted by the pancreas
Release stimulated by: Blood levels of amino acids, glucose
Functions: Promotes the storage of glucose, amino acids, and fats (anabolic, energy storage)
Term
Glucagon:
Definition
Secreted by the pancreas
Release stimulated by: blood glucose
Functions: Promotes the mobilization of fatty acids and glucose (glucogenolysis, lipolysis) (catabolic, energy usage)
Term
Explain exercise intensity and hormone effects of glycogen breakdown and fuel utilization:
Definition
The heavier the exercise, the faster glycogen is broken down.
Term
List the 4 steps in hormonal maintenance of plasma glucose during exercise:
Definition
1)Mobilization of glucose from liver glycogen stores
2)Mobilization of FFA from adipose tissue which spares blood glucose
3)Gluconeogenesis from amino acids, lactic acid, and glycerol
4)Blocking the entry of glucose in to cells which forces use of FFA as a fuel
Term
Differentiate fast acting hormones from slow acting hormones:
Definition
Fast acting hormones can react quickly to return the plasma glucose to normal. Aid in maintaining the plasma glucose concentration.
Slow acting hormones help to support actions of other hormones. Thyroxine, cortisol, and growth hormone. Regulate carbohydrate, fat, and protein metabolism
Term
What are the affects on trained individuals with regards to hormone concentration with exercise?
Definition
-Their plateau in plasma insulin drop occurs at a higher concentration
-They have an increase in plasma glucagon
-This indicates that exercise training results in better maintenance of cell fuel, supplies, and blood levels.
Term
What are the three standard terms for measurement?
Definition
1)Force
2)Work
3)Power
Term
What is the equation for work? What is work measured in?
Definition
Work = force x distance
measured in Joules
Term
What is the equation for power? What is it measured in?
Definition
power = work / time
measured in Watts
Term
What is the equation for force? What is it measured in?
Definition
Force = work / distance
measured in newtons
Term
Vertical displacement formula?
Definition
% grade x distance
Term
What is direct calorimetry?
Definition
Measurement of heat production as an indication of metabolic rate
Term
What is indirect calorimetry?
Definition
Measurement of oxygen consumption as an estimate of resting metabolic rate
Term
What is metabolic equivalent (MET)?
Definition
The ratio of a person's working metabolic rate relative to the resting metabolic rate. One MET is the caloric consumption of a person while at complete rest
Term
What is the relationship of VO2 and running and walking (with increasing speeds)?
Definition
A linear relationship
Term
What is the net efficiency calculation and what is it a measurement of?
Definition
(Work output / energy expended above rest) * 100
-Measurement of net exercise efficiency
Term
What are 3 factors that influence exercise efficiency?
Definition
1) Exercise work rate - Efficiency decreases as work rate increases
2) Speed of movement - There is an optimum speed of movement and any deviation reduces efficiency
3) Fiber composition of muscles - higher efficiency in muscles with greater percentage of slow fibers
Term
What are the 4 general functions of the nervous system?
Definition
1)Control of the internal environment - Nervous system works with endocrine system
2) Voluntary control of movement
3) Programming spinal cord reflexes
4) Assimilation of experiences necessary for memory and learning
Term
List out the organization of the nervous system:
Definition
1) Central Nervous system (CNS) - the brain and spinal cord
2) Peripheral Nervous system (PNS) - Neurons outside the CNS
-Sensory division - Afferent fibers transmit impulses from the receptors to CNS
-Motor division - efferent fibers transmit impulses from CNS to effector organs
Term
What do the dendrites do?
Definition
Conduct impulses toward the cell body
Term
What does the axon do?
Definition
Carries electrical impulses away from the cell body
-may be covered by schwann cells
Term
What do schwann cells do?
Definition
Form discontinuous myelin sheath along length of axon.
Term
What does the synapse do?
Definition
"contact" points between axon of one neuron and dendrite of another neuron.
Term
What properties characterize neurons as excitable tissue?
Definition
1) Irratibility - in response to a stimulus, ability to respond (transmit chemical stimulus) - neural impulse
2) Conductivity - transmission of the impulse along the axon
Term
What is the resting membrane potential and what is it caused by?
Definition
When at rest, the neurons are negatively charged. It is determined by concentrations of ions (Na+,K+,Cl-)across the membrane
The inside is negative relative to the outside!!!
Term
When the membrane potential is at rest, this is also known as what?
Definition
Polarized
Term
What is an action potential?
Definition
Active state - Occurs when depolarization reaches threshold - permeability of the membrane changes, allowing Na+ to enter the cell making the interior positively charged.
Term
What is repolarization?
Definition
Change in membrane permeability, restoring resting membrane potential.
Term
At resting membrane potential, what is the ion concentration inside and outside of the cell? depolarization? repolarization?
Definition
1)At rest, K+ inside and Na+ outside (negative inside)
2)Depolarization - Na+ comes into the cell making it positive
3)Repolarization - Na+ leaves the cell and K+ is restored making it negative inside again.
Term
How do neurons communicate across a synapses?
Definition
Using neurotransmitters - released from presynaptic membrane and binds to receptor on post synaptic membrane
Term
What are EPSPs? What are IPSPs?
Definition
EPSPs - Excitatory postsynaptic potentials - depolarization may/may not reach threshold.
IPSPs - Inhibitory postsynaptic potentials - causes hyperpolarization - A mechanism by which a membrane potential is made more negative inside with respect to the outside of the cell
Term
Define Temporal and spatial summations of EPSPs?
Definition
Temporal Summations - Summing several EPSPs from one presynaptic neuron
Spatial Summations - Summing from several different presynpatic neurons.
Term
What is proprioception?
what is kinesthesia?
Definition
Proprioception - ability to determine position of joint
Kinesthesia - sensation of joint motion or acceleration
Term
Explain the three types of proprioceptors:
Definition
1)Free nerve endings - touch & pressure
2)Golgi-type - in ligaments & joints
3)Pacinian Corpuscles - in tissues around joints, rapid response rate aids in detection of rate of joint movement
Term
What do muscle chemoreceptors sense and what alterations does this lead to?
Definition
They are sensitive to changes in the chemical environment surrounding a muscle. Provide CNS with information regarding the metabolic rate of muscular activity
-Hydrogen ion concentration
-Carbon dioxide (CO2)
-Potassium (K+)
Leads to alterations in
-Control of vascular, cardiac, pulmonary, endocrine, etc. (homeostatic control)
-ANS
Term
Explain the order of events of a reflex (3):
Definition
1)Sensory nerve sends impulse to spinal column
2)Interneurons activate motor neurons
3)Motor neurons control movement of muscles
Term
What is reciprocal inhibition?
Definition
EPSPs to muscles to withdraw from stimulus
IPSPs to antagonistic muscles
Term
What is a crossed extensor reflex?
Definition
opposite limb extended to support body during withdraw of first limb
Term
What is the somatic nerve function?
What is a motor unit?
What is the innervation ratio?
Definition
Somatic motor neurons of PNS - Responsible for carrying neural messages from spinal cord to skeletal muscles
Motor unit - Motor neuron and all the muscle fibers it innervates
Innervation Ratio - Number of muscle fibers per motor neuron
Term
With regards to the autonomic nervous system, what is the difference between the sympathetic and parasympathetic division with respect to action at effector organ and neurotransmitters used.
Definition
The sympathetic division releases norepinephrine which excites an effector organ
The parasympathetic division releases acetylcholine which inhibits an effector organ
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