Midterm 1 : Chapters 2,3,4,5 Flashcards
___________ fuel sources from which we obtain energy (ATP) and carbohydrate, fat, protein.
Energy Substrates
________ process of converting substrates into energy, and occurs at cellular level
Bioenergetics
_______ chemical reactions in the body
metabolism
energy released from a biological reaction can be calculated from .?
heat produced
What are the main fuels for exercise?
carbohydrates, fats, protein also referred to as carbon, hydrogen, oxygen, and sometimes nitrogen
energy from chemical bonds in food stored in high-energy compound: ?
ATP
all carbohydrate is converted to?
glucose
about _____ carbohydrates is stored in the body?
- 4.1 kcal/g
- 2,500 kcal
Carbohydrate converted to glucose would be the primary ATP substrate for ?
muscles & brain
When you have extra glucose what happens to it?
glucose is stored as glycogen in the liver and muscles
______ can be converted back to glucose when needed to make more ATP.
glycogen
When glycogen stores are limited; rely on dietary _____ to replenish.
carbohydrate
Fat is an efficient substrate with efficient storage with about how much stored in the body?
- 9.4 kcal/g
- +70,000 kcal stored in body
Fat substrate for prolonged, less intense exercise must be broken down from _____ into _______ and _______.
triglyceride; free fatty acids (FFAs); glycerol
Protein used as energy substrate during starvation should have _____ stored in the body and must be converted into glucose via gluconeogenesis.
4.1 kcal/g
Protein can also be converted into ______ via lipogenesis, for energy storage, and for cellular energy substrate.
FFAs
Free energy released at a controlled rate depends on 2 factors:?
- availability of the primary substrate
- enzyme activity
What do enzymes do?
- are protein molecules
- do not start chemical reactions
- facilitate breakdown (catabolism) of substrates
- lower the activation energy form a chemical reaction
T/F ? Enzyme activity affects metabolic rate
True
if there is an increase in enzymes o enzyme activity the there is _____ in product.
an increase
T/F ? ATP stored in small amounts until needed.
True
Phosphorylation can occur ?
in absence or presence of O2.
What are the three ATP synthesis pathways:
- ATP-PCr system (anaerobic metabolism)
- Glycolysis (anaerobic metabolism)
- Oxidative phosphorylation (aerobic metabolism)
ATP-PCr system starts with?
phosphocreatine (PCr)
_____ energy cannot be used for cellular work, but can be used to reassemble ATP.
PCr
_____ replenishes ATP stores during rest.
PCr
Glycolytic system uses ____ process.
anaerobic
pathway starts with ________, ends with _______. there are 10 to 12 enzymatic reactions total and all steps occur in cytoplasm.
glucose-6-phosphate; pyruvic acid
pathways have an enzyme that control overall rate, can create bottleneck at an early stage, activity influenced by NEGATIVE FEEDBACK, and slows overall reaction, prevents runaway reaction would be considered as?
rate-limiting enzyme
What is the most common rate-limiting enzyme?
PFK
What would be the cons of the glycolytic system?
- low ATP yield, inefficient use of substrate
- lack of o2 converts pyruvic acid to lactic acid
- lactic acid impairs glycolysis, muscle contraction
What would be the pros of the glycolytic system?
- allows muscles to contract when o2 limited
- permits shorter term, higher-intensity exercise
T/F ? Oxidative Phosphorylation uses the aerobic process.
True
Oxidative Phosphorylation occurs in the ?
mitochondria
what are the 3 stages of oxidation of carbohydrate cycle?
stage 1: glycolysis
stage 2: Krebs cycle
stage 3: electron transport chain
pyruvic acid -> acetyl-CoA, then enters?
Krebs cycle
NADH and FADH2 molecules carry ____ and ___ to the electron transport chain.
H+; electrons
_________ is a group of protein complexes located in the inner mitochondrial membrane.
electron transport chain
_____ is the final electron acceptor.
oxygen
many chemical compounds are classified as fats such as:
- phospholipids
- cholesterol
- triglycerides
________: major fat energy source. These are stored in adipocytes (fat cells), between muscle fibers, and within muscle fibers.
triglycerides
what is the process of the oxidation of fat?
- broken down to 1 glycerol + 3 FFAs
- Lipolysis, carried out by lipase
- FFA transported by blood
- enters muscle by diffusion
- … yields 3 to 4 times more ATP than glucose … but slower than glucose oxidation
- this process is called beta-oxidation
________: structural building blocks, enzymatic function, energy under some circumstances.
protein
Where did the lactate come from?
during glycolysis, in anaerobic conditions, pyruvic acid takes hydrogen ions to form lactic acid
What are the 3 ways muscles can utilize?
- oxidation
- lactate shuttle
- the cori cycle
Oxidation occurs in cells with ___________.
high mitochondrial density ( mostly in type I fibers)
What is the Cori Cycle?
starts in muscle as glucose then goes through fast glycolysis to lactate then blood lactate to liver back into glucose then out of the liver as blood glucose and back into the muscle as glucose.
Direct Calorimetry: substrate metabolism efficiency has ___ of substrate energy from ATP, and _____ of substrate energy from heat.
40% ; 60%
Heat production ______ with energy production.
increases
What are the pros of the direct calorimetry?
- directly measures heat
- accurate for total body energy expenditure over time
What are the cons of the direct calorimetry?
- expensive, slow to generate results
- cannot detect rapid changes in energy expenditure
- exercise equipment adds extra heat
- not all heat produced leaves the body; some stored
- sweat affects measurements and calculations
Indirect calorimetry is an estimate of?
total body energy expenditure based on O2 used, CO2 produced during oxidative phosphorylation.
Called indirect calorimetry because?
- heat production not directly measured
- estimate of total body energy expenditure
Indirect calorimetry can also estimate the composition of ___ ____
fuel oxidized
CARBOHYDRATE: During the oxidation of a glucose molecule ___ O2 are consumed and ___ CO2 are produced.
6 ; 6
FATS: ___ CO2 are produced for every ___ O2 consumed.
16 ; 23
When hyperventilation occurs there is an increase in _____ elimination.
CO2
______: rate of energy use by body.
metabolic rate
________: rate of energy expenditure at rest.
basal metabolic rate (BMR)
V02 max expressed in “absolute” terms is used by?
absolute volume of O2 used by entire body
V02 max expressed in “relative” terms is used by?
normalized for body weight
__________: point at which blood lactate accumulation increases markedly
lactate threshold
an increase in lactate threshold _____ entrance performance
increases
as athlete become more skilled, use less energy for given pace = ?
more economical
what are the two muscle sorenesses?
- acute muscle soreness
- delayed-onset muscle soreness
acute muscle soreness occurs?
during and immediately after exercise
delayed-onset soreness occurs?
one to two days later
During acute muscle soreness … ?
- tissue edema (plasma fluid into interstitial space)
- disappears within minutes to hours
major cause for DOMS is?
eccentric contractions
Where are the hormone receptors located?
- steroid (lipid soluble): receptors in cytoplasm or nucleus of target cell
- non steroid (not lipid soluble): receptors on membrane of target cell
T/F ? Nervous system is referred to as electrical signals.
True
Steroid hormones come from?
cholesterol
Phospholipid is made up of?
fat cell walls
What is a hormone-receptor complex?
when a hormone binds to a cell
when the hormone-receptor complex enter nucleus what happens?
- binds to DNA and activates certain genes
- in response, mRNA synthesized within nucleus
- mRNA enters cytoplasm, promotes protein synthesis
Steroid hormone actions consist of which proteins?
- enzymes
- structural proteins
- regulatory; alters enzyme function
The endocrine system is a ?
communication system
Nonsteroid hormone actions which would be not lipid soluble cannot cross?
cell membrane
For nonsteroid hormone actions; the receptors on the cell membrane ?
trigger release of intracellular second messengers
- carry out hormone effects
- intensify strength of hormone signal
What are the major glands responsible for metabolic regulation?
- anterior pituitary gland
- thyroid gland
- adrenal gland
- pancreas
the anterior pituitary gland is located?
in the front of the brain
The growth hormone comes from?
the anterior pituitary gland
Growth hormone effects?
- potent anabolic hormone
- builds tissues, organs
- promotes muscle growth (hypertrophy)
- stimulates fat metabolism
GH released during aerobic and resistance exercise occurs when?
- proportional to exercise intensity
- remain elevated after exercise
What does the Thyroid gland secrete?
T3 and T4
Where is the thyroid gland located?
in the neck
What do T3 and T4 do?
- increases:
- metabolic rate of all tissues
- protein synthesis
- # and size of mitochondria
- glucose uptake by cells
- rate of glycolysis and gluconeogenesis
- FFA mobilization
Where are the adrenal glands located?
above each kidney
What are the two parts of the adrenal gland?
- outter section is referred to as the adrenal cortex
- deeper section is referred to as the adrenal medulla
when the adrenal medulla is stimulated by sympathetic nervous system what happens?
catecholamines are released
- causes “fight-or-flight” response
- epinephrine 80% and norepinephrine 20%
when catecholamine is released what happens?
- increase in heart rate, contractile force, blood pressure
- increase in glycogenolysis (glycogen is being broken down)
- increase in lipolysis (fat or trigclerides are being broken down)
increase in blood flow to skeletal muscle
The adrenal cortex release?
cortisol (a hormone that breaks things down and catabolic)
when cortisol is released what happens?
- increases gluconeogenesis (making new glucose) for fuel
- increases FFA mobilization
- spares glucose for brain
- protein catabolism for repair, enzyme production, gluconeogenesis
Where is the pancreas located?
behind and slightly below the stomach
What are the 2 major hormones that come from the pancreas?
- insulin
- glucagon
Insulin and glucagon work together to?
control plasma glucose
During hyperglycemia ( after a meal), the pancreas releases?
insulin
what is the main function of insulin?
lowers (blood glucose)
- counters hyperglycemia
- increases glucose transport into cells (especially muscle)
- increases glycogenesis (creating glycogen)
- inhibits gluconeogensis
During hypoglycemia, the pancreas releases?
glucagon
what is the main function(s) of glucagon?
increases (blood glucose)
- counters hypoglycemia
- increases glycogenolysis (liver glycogen to glucose)
- increases gluconeogenesis (causes the formation of new sugar)
What happens to insulin during exercise?
works better during exercise because it is able to bind receptors on muscle cells
what happens to glucagon during exercise?
glucagon increases to maintain plasma glucose
glucose must be available to ?
tissues
adequate plasma glucose during exercise requires balance between?
- glucose release by liver
- glucose uptake by muscles
Hormones that increase circulating glucose would be?
glucagon, epinephrine, norepinephrine which are all part of glycogenolysis
_____: enables glucose uptake in muscle.
insulin
during exercise insulin concentrations?
decrease; due to an increase in insulin sensitivity during exercise
hormonal regulation of fluid and electrolytes during exercise causes?
- water to shift from plasma volume to interstitial and intracellular spaces
- sweating increases during exercise
the fluid in our blood is _____ plasma volume during exercise.
decreasing
when plasma volume decreases then ?
there is a decrease in blood pressure and an increase heart strain
which glands are involved in monitoring fluid levels and electrolyte balance?
- posterior pituitary gland
- adrenal cortex
- kidneys (not only a target organ; also a gland)
Posterioir pituitary gland secretes?
antidiuretic hormone (also called ADH or vasopressin)
what does antidiuretic hormone do?
- increases water reabsorption by kidneys, less water excreted in the urine (antidiuresis)
- minimizes water loss and severe dehydration
what does adrenal cortex secrete?
aldosterone
what does aldosterone effect?
there is an increase in sodium retention by kidneys which leads to an increase in water retention via osmosis
kidneys release?
erythropoietin (EPO) that targets bone marrow to stimulate red blood cell (RBC) production
Kidneys are a target tissue for?
ADH and aldosterone; can also stimulate renin-angiotensin-aldosterone mechanism
What is happening during renin-angiotensin-aldosterone mechanism?
- kidneys sense a decrease in blood volume
- release enzyme called renin into circulation
in circulation renin converts angiotensinogen molecule?
angiotensin I
in the lungs, angiotensin-converting enzyme (ACE): converts?
angiotensin I to angiotensin II
When angiotensin II reaches adrenal cortex and stimulates?
aldosterone via osmosis
gherlin is released?
by the stomach when it is hungry
leptin decreases?
hunger
people who are obese have?
higher leptin levels but they are resistant to it because the signal is not transmitted through the hypothalamus
hormonal regulation of calorie intake during acute exercise causes?
mod-vig aerobic exercise, decreases ghrelin temporarily which will reduce hunger
hormonal regulation of calorie intake during chronic exercise causes?
- no change in ghrelin response on people who do not lose weight during exercise training
- ghrelin increases in those who do lose weight
nervous system = _______ communication
electrical
endocrine system = ______ communication
chemical
the endocrine system maintains homeostasis via?
hormones
what are hormones and what do they do?
- chemicals that control and regulate cell/organ activity
- secreted into blood
- act on target cells (has specific hormone receptors)
Hormones are categorized as?
steroid or nonsteroids
What are steroid hormones?
steroids derived from cholesterol, lipid soluble; diffuses through membranes, the major glands that secrete steroid hormones are testes, ovaries, and adrenal cortex
what are non steroid hormones?
steroids that are not lipid soluble; cannot cross membranes, divided into two groups; protein/peptide hormones
the central nervous system consists of?
brain and spinal cord
the peripheral nervous system has which two major nerves?
the sensory (afferent) nerves and effector (efferent) nerves
neurons respond to stimuli and convert those messages to an electrical signal called a _______.
nerve impulse
What is a neuron?
basic structural unit o nervous system
the neuron has three major regions what are there?
- cell body (soma)
- dendrites
- axon
What does the cell body contain and what happens inside?
contains nucleus, and cell processes radiate out
what does the cell body contain and what happens?
dendrites are the receiver cell processes and carry an impulse towards the cell body
what is the axon and what happens?
the axon is the sender cell process, starts at the axon hillock, end branches, and axon terminals
electrical signal for communication between _____ and _____.
periphery; brain
when charges across membrane differ, membrane is _________.
polarized
When there is a difference in electrical charges between outside and inside of cell this is referred to as the ?
resting membrane potential (RMP)
according to the resting membrane potential (RMP) the inside is more negative relative to outside: ?
- 70 mV
- caused by uneven separation of charged ions
- high sodium outside cell
- medium potassium inside the cell
RMP maintained in 2 ways:
- membrane more permeable to K+ due to open K+ channels
- K+ will move to less concentrated areas - Na+ -K+ pump (primary mechanism)
- actively transports (requires ATP) three Na+ out of cell and two K+ into cell
occurs when inside of cell becomes more positive, more Na+ channels open; Na+ enters cell (influx), and is required for nerve impulse to arise and travel would be considered?
depolarization
occurs when inside of cell becomes more negative even below -70 mV, more K+ channels open, K+ leaves cell (efflux), makes it more difficult for nerve impulse to arise is considered as?
hyperpolaarization
depolarization and hyper polarization contribute to nervous system function via?
graded potentials (GPs)
______: localized changes in membrane potential. generated by incoming signals from dendrites, help cell body decide whether to pass signal on.
graded potentials
what happens when excitatory postsynaptic potential (EPSP) are in affect?
- na+ channels open = Na+ influx
- depolarization
what happens when inhibitory postsynaptic potential (IPSP) is in effect?
- K+ channels open = K+ efflux
- hyperpolarization
Strong EPSP will lead to an _________.
action potential (AP)
if GP reaches ____ to ____ (threshold mV), AP will occur.
-55; -50
________: keeps total of EPSPs and IPSPs.
axon hillock
what are the 2 characteristics that determine propagation speed: ?
- axon diameter
- myelin
What is the myelin and what happens within it?
- fatty sheath around axon (formed by Schwann cells)
- not continuous (spaces are nodes of Ranvier)
- saltatory conduction
- speeds up propagation
- multiple sclerosis: degeneration of myelin; loss of coordination
For neurons to communicate, Paps transfer from a _______ to _____ neuron.
presynaptic; postsynaptic
site of neuron-to-neuron communication: ?
synapse
axon terminals contain?
neurotransmitters
neurotransmitters help with?
- chemical messengers
- carry electrical AP signal across synaptic cleft
- bind to receptor on postsynaptic surface
- stimulate GPs in postsynaptic neuron
neurotransmitters bind to receptor at special site:?
motor end plate
diencephalon contains?
thalamus and hypothalamus
what is the thalamus in charge of?
the sensory relay center; all sensory input (except smell) enters here, regulates what sensory input reaches conscious brain (important for motor control)
what is the hypothalamus in charge of?
- maintaining homeostasis (by regulating internal environment) through blood pressure, heart rate and contractility, respirations, digestion, body temperature, thirst and fluid balance, neuroendocrine control, appetite and food intake, sleep-wake cycles
where is the cerebellum located?
behind the brain stem
what is the cerebellum in charge of?
- controls rapid, complex movements, coordinates timing, sequence of movements, compares actual to intended movements and initiates correction
- assists primary motor cortex and basal ganglia in executing and refining movements
What does the brain stem do?
relays information (both ways) between the brain and spinal cord
what is the brain stem composed of?
- midbrain
- pons
- medulla oblongata
__________ are specialized neurons in brain stem that coordinates skeletal muscle function and tone, controls cardiovascular and respiratory function, and is the pain control system (analgesia)
reticular formation
the spinal cord is composed of tracts of nerve fibers that permit two-way conduction of nerve impulses such as?
- ascending afferent (sensory) fibers
- descending efferent (motor) fibers
the peripheral nervous system connects to brain and spinal cord via _____ pairs of nerves
43
____ pairs of cranial nerves (originate from brain)
12
___ pairs of spinal nerves (originate from spinal cord)
31
what are the major families of sensory receptors?
- mechanoreceptors (pressure, touch, vibrations, stretch)
- thermoreceptors (temp.)
- photoreceptors (light)
- chemoreceptors (orders, O2, CO2, glucose, electrolytes)
____________: located in joint capsules, sensitive to joint angles and rate of angle change, they sense joint position and movement.
joint kinesthetic receptors
_______: sensitive to muscle length, rate of length change
muscle spindles
________: sensitive to tension applied by muscle to its tendon, provides information about strength of contraction.
Golgi tendon organs
what two divisions does the motor (efferent) division consist of?
autonomic and somatic
________: regulates visceral activity
autonomic
______: stimulates skeletal muscle activity
somatic
_________: fight or flight, increased heart rate, contractility, coronary vessel dilation, peripheral vasodilation for blood flow, etc.
sympathetic system
______ : rest and digest, stimulates an increased digestion, uirination, conservation of energy, decreased heart rate, decreased diameter of vessels and airways
parasympathetic system
