A&P Exam 2

Question 1

Pathways of ATP Synthesis

Answer 1

Anaerobic (makes some ATP)
glycolysis breaks down glucose to pyruvic acid in cytoplasm – occurs w/o oxygen, produces lactic acid (lowers pH and stimulates pain neurons)
Aerobic (makes a lot of ATP)
Continues oxygen supply needed, makes h2o and co2

Question 2

Anaerobic glycolysis

Answer 2

E source for peak muscular activity
produces 2 ATP molecules per molecule of glucose
Breaks down glucose from glycogen stored in skeletal muscles
Produces lactic acid

Question 3

Muscle Energy

Answer 3

Resting (fatty acid catabolized in mitochondria; ATP produced is used to build energy reserves)
Moderate activity (glucose and fatty acids catabolized in mitochondria and ATP is used for contraction)
Peak Activity (Most ATP produced thru glycolysis with lactic acid as by-product; mitochondria only supplies 1/3 ATP consumed) -- Oxygen consumption rates increase initially 3-4 then levels off --> to allow mitochondria to make enough ATP

Question 4

What limits muscle energy during exercise?

Answer 4

Depletion of glycogen, blood glucose, loss of fluid and electrolytes

Question 5

Fatigue

Answer 5

progressive weakness and loss of contractility from prolonged use
Causes:
ATP synthesis declines as glycogen is consumed
ATP shortage causes failure of membrane potential and excitability
Lactic acid lowers pH of sarcoplasm inhibiting enzyme function
Motor nerve fibers use up their acetylcholine

Question 6

Endurance

Answer 6

ability to maintain high intensity exercise as based on maximum oxygen uptake and nutrient availability
VO2 max –> proportional to body size, peaks at age 20, larger in trained athletes and males

Question 7

What is endurance dependent on?

Answer 7

Supply of organic nutrients
Fatty acids, amino acids, and glucose
Carbohydrate loading is used by some athletes to pack glycogen into muscle cells

Question 8

Oxygen Debt

Answer 8

vigorous energy causes dramatic change in muscle chemistry
After exercise, rate of oxygen uptake doesn’t immediately return to previous levels
Oxygen Debt = extra amount of O2 needed to return body to resting state (typically extra 11 liters are consumed, depends on health of person tho)

Question 9

What are the purposes for extra oxygen during oxygen debt?

Answer 9

Replaces oxygen reserves (myoglobin, blood hemoglobin, in the air of the lungs and in the plasma)
Reconverting lactic acid to glucose in kidneys and liver (Cori Cycle)
Serving elevated metabolic rate that occurs as long as body temperature remains elevated by exercise

Question 10

What is the best diet for exercising?

Answer 10

High carb! you have extra glycogen storage for your body and you recover faster
Fats and Proteins have glucose, but it needs the liver to convert it to glycogen and it takes way longer and you won’t exercise as well
(of course, mixed diet is the best, just don’t cut out your carbs and sugar is worse than fat)

Question 11

What are the functional characteristics of muscle fiber types?

Answer 11

Slow-twitch: type 1 fibers, 100 msec/twitch (fibers contract slowly and fatigue resistant (more mitochondria, extensive capillary supply)
Fast-twitch: type 2 fibers, 7.5 msec/twitch

Question 12

What are the two ATP forming pathways?

Answer 12

oxidative fibers (slow-twitch) 
glycolysis fibers (fast-twitch)

Question 13

White muscle

Answer 13

mostly fast-twitching, glycolytic

Question 14

Red muscle

Answer 14

slow oxidative, red because of capillaries, myoglobin, and mitochondria

Question 15

Strength and conditioning

Answer 15

Factors that increase strength of contraction
muscle size and fascicle arrangement, size of motor units, and frequency of stimulations, length of muscle at start of contraction and fatigue

Resistance training (weight lifting)
stimulates hypertrophy due to synthesis of myofilaments

Endurance training (aerobic exercise)
produces increase in mitochondria, glycogen, and density of capillaries

Question 16

Neurons

Answer 16

generate and transmit nerve impulses

Question 17

Neuroglia (glial cells)

Answer 17

supporting cells (all the other cells in nervous tissue that’s not neurons) – brace, separate, and protect neurons (includes phagocytes)

Question 18

Central Nervous System

Answer 18

brain and spinal cord enclosed in bony coverings

Question 19

Peripheral Nervous System

Answer 19

all nervous tissue outside CNS

Question 20

Nerve

Answer 20

bundle of nerve fibers (bundle of axons) with connective tissues and blood vessels

Question 21

Functional Division of PNS (sensory)

Answer 21

Sensory (afferent) divisions (receptors to CNS)
Receptos are sensory structures that detect change (ie: neurons or specialized cells like eye, ear, tactile corpuscles, Pacinian and Meissner’s)

Question 22

Functional Division of PNS (motor)

Answer 22

Motor (efferent) division (CNS to effectors)
Effectors are target organs that respond by doing something
Divided into SNS and ANS

Question 23

Somatic Nervous System (SNS)

Answer 23

Controls skeletal muscle contractions

Voluntary and involuntary

Question 24

Autonomic Nervous System (ANS)

Answer 24

Visceral motor system
Autonomic regulation of smooth muscle, cardiac muscle, and glandular secretions at SUBCONCIOUS LEVEL (we don’t have control over this)

Question 25

The Two Sections of the Autonomic Nervous System (ANS)

Answer 25

Sympathetic nervous system
General action to mobilize body’s resources under stress, to induce the fight-or-flight response
Continuously active at basal level to maintain homeostasis
Parasympathetic Nervous System
Slows heart rate, increase intestinal and gland activity, and relaxes sphincter muscles

Question 26

Cocaine

Answer 26

inhibits removal of dopamine from synapses in some areas of the brain
Can cause long-term changes in reward system (even immediate use can cause intense changes in the VTA/Nucleus Accumbens)

Question 27

Serotonin

Answer 27

CNS neurotransmitter: regulation of mood, appetite, sleep, muscle contraction, and some cognitive functions including memory and learning
SSRI’s – Selective Serotonin Reuptake Inhibitor (inhibits reabsorption of serotonin by synaptic knobs)

Question 28

Gamma-aminobutyric acid (GABA)

Answer 28

Inhibitory effects
Function not well known, abundant in CNS and regulates neuronal excitability
GABA release appears to reduce anxiety (ie: Xannies)

Question 29

Inhibitory GABA-ergic Synapses

Answer 29

Signal from axon hillock releases GABA, crosses synaptic gap and causes the release of Cl-

Question 30

Neuropeptides

Answer 30

Larger than neurotransmitters (2-40 amino acids)
Stored in axon terminals as larger secretory granules - due to size, don’t need larger concentration and lasts longer due to longer time needed to break them down
Some can be triggered from non-neural tissue (ie: hunger pains/food craving from the stomach) and can also act as hormones

Question 31

Neuromodulators

Answer 31

alter rate of neurotransmitter release (presynaptic neuron or change in postsynaptic cell's response to NT)
Includes opiates (endogenous, natural, and semi-synthetic) affecting nociceptors (pain perceptor)

Question 32

Mechanisms of neurotransmitter function

Answer 32

Direct (opening and closing gate of ion channel)

Indirect (using a secondary messenger to open the gate

Question 33

Cessation and Modification of a Neural Signal

Answer 33

diffusion of neurotransmitter away from synapse
reuptake
breaking down neurotransmitter (acetylcholinesterase)

Question 34

Spacial Summation

Answer 34

simultaneous stimuli applied at different locations that have cumulative effect
more than 1 synapse active at a time