Unit 2 Flashcards
What is O2 consumption at rest?
0.25L/min
3.5ml/kg/min
1 MET
what is 1 MET
oxygen consumption at rest, Metabolic Equivalent
When does ATP consumption increase at the start of exercise?
immediately
Oxygen Deficit definition
lag in usage of oxygen at the start of exercise (endurance trained individuals have a lower deficit)
Why do trained individuals have a lower oxygen deficit?
Better developed aerobic bioenergetic capacity due to cardiovascular
(more capillaries) and muscular adaptations (greater mitochondrial
volume)
what is EPOC?
excessive post-exercise oxygen consumption, repay oxygen debt and resynthesis of phosphocreatine in muscles, replenish myoglobin and hemoglobin stores
what is VO2 max?
maximal oxygen uptake, increases linearly during exercise until ceiling is reached, influenced by training and genetics
what physiological factors influence vo2 max?
ability of the cardiorespiratory system to deliver oxygen, ability of muscles to use oxygen to produce ATP
Lactate threshold definition
the work rate at which blood lactic acid rises
systematically during incremental exercise.
what three factors influence fuel selection during exercise?
intensity, duration, availability of fuels
what fuel source do we use more of the longer we exercise?
fat
hormone definition
chemical message that travels through the blood to target tissues and cells
what are classes of hormones?
based on chemical makeup, amino acids (catecholamines), peptides/proteins, steroids
what is hormones role in the body?
fine tune physiological processes like growth, metabolism, BP, and reproduction
how are hormones regulated?
homeostatically
what effects the effect of a hormone?
concentration, number of receptors, affinity of receptors
how do steroid hormones signal?
travels to the nucleus to activate genes
where are hormones secreted from?
endocrine glands: Hypothalamus and pituitary glands, thyroid and parathyroid glands, Adrenal gland, Pancreas, Testes and ovaries
what does the hypothalamus do?
exerts homeostatic control over hormone secretion
what does somatostatin do?
exerts negative feedback on hormone secretion from various glands
what does growth hormone do?
stimulates the release of insulin-like growth factors, reduces the use of plasma glucose, increases gluconeogenesis, mobilizes fatty acids
what do IGF-1 do?
amino acid uptake and protein synthesis, long bone growth
what does the thyroid gland do?
secretes triiodothyronine (T3) and thyroxine (T4) which increase metabolic rate
Adrenal medulla gland
secretes catecholamines epinephrine and norepinephrine
what is the effect of catecholamines on beta receptors?
increases heart rate, breathing and metabolism
what is the effect of catecholamines on alpha receptors?
counters the effects on beta receptors, more selective
what does the adrenal cortex gland do?
secretes steroid hormones: sex steroids and glucocorticoids
what does cortisol do?
slow-acting catabolic, increased by stress, peak in am, stimulate breakdown of triglycerides
what does testosterone do?
anabolic steroid, promotes tissue building, increases strength and power, androgenic: promotes masculine characteristics
what does estrogen and progesterone do?
establish and maintain reproductive function
what does the pancreas do?
secretes insulin (from beta cells) and glucagon (from alpha cells)
what doe glucagon do?
promotes the production/release of fatty acids and glucose
what does insulin do?
promotes the storage of glucose, amino acids, and fats
how is blood glucose homeostasis maintained during exercise?
release of glucose from liver, production of new glucose, decrease in glucose uptake in cells that aren’t the brain, release of free fatty acids from adipose tissue
which hormones does adipose tissue secrete?
leptin and adiponectin
what does leptin do?
suppresses appetite, enhances insulin sensitivity
what does adiponectin do?
increases insulin sensitivity and fatty acid oxidation
what hormone does skeletal muscle produce?
myokines
Immunity definition
protects the body against foreign agents (pathogens)
what is the adaptive immune response
the body learns to identify pathogens
what do B cells do
produce antibodies in response to an antigen
what do T cells do?
respond to antigens based on protein receptors on their surface
What do killer T cells do
attack our own cells that are infected with a virus
what do helper T cells do?
secrete cytokines to recruit more immune cells to the infection site
what does acute inflammation do?
short term response to injury, vasodilation, increased blood flow
what does chronic inflammation do?
persistent infection, increased circulation of cytokines
what is the risk of exercise on upper respiratory tract infection?
J shaped curve, too little and too much is bad
sensory nervous system definition
detects stimuli and transmits information from receptors to CNS (input)
Somatic sensory system definition
sensory input that is consciously perceived from receptors
visceral sensory system definition
sensory input that is not consciously perceived from receptors
motor nervous system definition
initiates and transmits information from the CNS to effectors
Somatic motor system definition
Motor output that is consciously or voluntarily controlled
Autonomic motor system definition
motor output that is not consciously or involuntarily controlled
Afferent definition
towards the brain
Efferent definition
away from the brain
cell body of a neuron
contains the nucleus
dendrites
conduct impulses toward the cell body
Axon
carries electrical impulse away from cell body, covered by schwann cells (myelin sheath)
Synapse
small gap between presynaptic neuron and postsynaptic neuron
neurotransmitters
chemicals released at synapse, changes electrical charge which depolarizes pre synaptic neuron
Action potential definition
electrical response of cell, all or none law
Proprioceptors definition
tell CNS info about body position, found in joints and muscles
Muscle spindle definition
info about length and rate of shortening, stretch promotes reflex contraction
Kinesthesia definition
conscious recognition of the position of body parts, recognition of speed of limb movement
Golgi tendon organ definition
provides information about muscle force production
Skeletal muscle chemoreceptors definition
sensitive to changes in the chemical environment surrounding muscle fibers, contraction increases acidity an CO2 which increases HR and breathing
Somatic motor function
motor neurons located within spinal cord, carry neural messages from spinal cord to skeletal muscles
Motor unit definition
motor neuron and all the muscle fibers it innervates
Neuromuscular junction definition
where neuron and muscle meet
Innervation ratio
number of muscle fibers innervated per motor neuron
Fine motor control has low innervation ratio
Joints have high innervation ratio
motor unit recruitment and size principle
recruit more muscle fibers by activation more motor units, smallest motor units recruited first during exercise
Three types of motor units
Type S (slow) - smallest
Type FR (fast, fatigue resistant)
Type FF (fast, fatigable) - largest
Autonomic nervous system function
maintains homeostasis by effecting organs not under voluntary control
sympathetic division of autonomic nervous system
release epinephrine and norepinephrine, dilate pupils, increase HR, slow digestion
Parasympathetic division of autonomic nervous system
releases acetylcholine, constricts pupils and bronchi, slow HR, relax blood vessels, promote digestion
how does exercise enhance brain health?
improves learning and memory, neurogenesis, vascular function, reduces depression
what are the three types of muscle actions
concentric, eccentric, isometric
epimysium definition
surrounds entire muscle
perimysium definition
surrounds bundles of muscle fibers
endomysium definition
surrounds individual muscle fibers
satellite cells definition
support growth and repair of skeletal muscle
skeletal muscle fibers definition
multinucleated cells with myofibrils that contain the contractile proteins actin and myosin
sarcomere definition
the contractile unit of skeletal muscle
Sliding filament theory
muscle contracts because actin and myosin slide along each other, shortening sarcomere length
which muscle cell has the least amount of mitochondria
Type 2x - fast fibers
role of calcium in muscle contraction
allows actin and myosin to bind, stored in the sarcoplasmic reticulum
tetanus definition
continuous firing of motor neurons creating maximum force
muscle fatigue definition
decline in muscle power output
metabolic or mechanical limitations
how does aging affect muscle mass and function?
10% between age 25-50
additional 40% between age 50-80
resistance training can delay loss
sarcopenia definition
age-related loss of muscle mass and function
Role of acetylcholine in muscle fibers
causes depolarization of muscle fiber (contraction), released by motor neuron
muscular dystrophy
hereditary defects in muscle protein, results in loss of muscle fibers and weakness
3 functions of the cardiorespiratory system
transport oxygen, remove CO2, regulate body temperature
how does blood flow change during exercise?
increased cardiac output, increased blood flow to active muscle which reduces blood flow to inactive organs
plasma
liquid portion of blood, contains small proteins, nutrients, etc.
red blood cells
carry oxygen via hemoglobin
parts of blood
plasma, white blood cells, platelets, red blood cells
hematocrit definition
percentage of blood as red blood cells, usually 40-45%
heart
created pressure to pump blood, part of circulatory system
arteries and arterioles
carry blood away from the heart, part of circulatory system
veins and venules
carry blood toward the heart, part of circulatory system
capillaries
exchange of O2 and CO2 and nutrients with tissues, part of circulatory system
epicardium definition
connective tissue of the heart
myocardium definition
heart muscle
endocardium definition
acts like a blood vessel
systole definition
contraction phase of cardiac cycle, ejects blood
Diastole definition
relaxation phase of cardiac cycle, fills with blood
determinants of mean arterial pressure
cardiac output x total vascular resistance
arterial blood pressure
systolic/diastolic
short term regulation of blood pressure
by sympathetic nervous system and baroreceptors in aorta and carotid arteries
long term regulation of blood pressure
kidneys via control of blood volume
hypertension
blood pressure above 140/90 mmHg
cardiac output
amount of blood pumped by the heart each minute
Q=HR x SV
what causes low resting HR?
parasympathetic nervous system
how does exercise influence HR?
initial ride due to decreased parasympathetic activity (100bpm), subsequent increase increase in sympathetic activity to SA node
where does gas exchange occur in the lungs?
alveoli (alveolar wall)
how does movement of air occur?
pressure differences between intrapulmonary pressure and atmospheric pressure
pulmonary ventilation definition
movement of air into and out of the lungs
V=Vt x frequency
Tidal volume (Vt)
volume of gas moved per breath
Oxyhemoglobin definition
Hemoglobin (Hb) bound to oxygen (how 99% of oxygen is transported in the blood)
how is CO2 transported in the blood
dissolved in plasma (10%)
Bound to Hb (20%)
Bicarbonate (70%)
what are the two parts of the control of ventilation?
inspiration and expiration
inspiration definition
inhale air, controlled by control center located in medullar oblongata
expiration definition
exhale air, input from higher brain, muscle mechanoreceptors, and chemoreceptors
