ATP

Adenosine Triphosphate

biochemical pathways that release this energy are coupled to the production of ATP from Adenosine Diphosphate (ADP)

common energy currency in the cell

contains high-energy bonds, which, when broken release energy

require oxygen beause they terminate in the transfer of electrons, ultimately to oxygen, thus forming water, in the ETC

beta oxidation, glycolysis and the citric acid cycle

catabolism of carbs ultimately into acetyl CoA and other substrates for ETC

doesn't require energy

Citric Acid Cycle

tricarboxylic acid cycle

Kreb's Cycle

catabolism of carbs into some ATP and lactic acid

doesn't require oxygen

produce ATP faster but can only perform at its maximal rates for short periods of time

ATP can be converted to physical work with

50% resulting in heat and 50% as work

20-30 Caolories of work can be performd and 70-80 Calories given off as heat

thermal unit of energy

amount of heat required to raise the temp of one gram of pure water 1 degree celsius

1 C or kCal=1000 small calories

1 c = 4.17 J

the rate wat which energy is expended by the body per unit of time

reported relative to the subject's body surface area because diferent size indidivudals expend different amounts of energy

kcal/m²/hr

determining the subject's oxygen consumption

easier and practical

used to determine energy expenditure during exercise but only accurate if the subject is exercising at a low/moderate intensity

caloric equivalent

energy equivalent of oxygen

the amount of energy expended per liter of oxygen consumed by the subject

carbs = 5.05 kcal/L

fats = 4.70 kcal/L

proteins = 4.60 kcal/L

carb/protein = 4 kcal per gram

fat = 9 kcal per gram

alcohol = 7 kcal per gram

4.825 kcal/L

rely more on fats than carbs

rate at which oxygen is being consumed and it can be reported as an absolute value (L/min) or relative body mass (ml/kg/min)

used for calculation for metabolic rate

determined by the amount of air moved in and out of the lungs, and the amount of oxygen extracted from the air

heat production

energy expenditure

amount of energy a person is expending per hour and is usually reported in kcal/hr

L/hr x Kcal/L

subject is connected to a closed system respirometer

spirometer bell filled with oxygen

expired carbon dioxide is removed

the bell falls and rises with each inspiration and expiration

movements recored in kymograph

bell gradually lowers as oxygen is consumed and expired carbon dioxide is removed

oxygen consumption measued by open spirometry

metabolic chart

Standard Temperature, Pressure, Dry conditions

STPD

0 degree Celsius

760mm Hg

no water vapor

under these conditions one liter of any ideal gas would contain the same number of gas molecules

the volume of any gas accurately represents the number of gas molecules

the ratio of carbon dioxide produced to the oxygen consumed at the cellular level

carbs = 1

fat = .7

oxygen and hydrogen are present in carbs in the same proportions as water, whereas in teh various fats extra oxygen is necessary for the formation of water

the ratio of carbon dioxide produced to the oxygen consumed at the whole body level

VCO₂
VO₂

need to know what caloric equivalent value to use in our calculation of metabolic rate

.82 and represents a blend of 40% carbs and 60% fat metabolism

4.875 Kcal/L

the complete oxidation of proteins can't be completely accounted for by carbon dioxide and water (have nitrogen that must be accounted for)

urinary nitrogen excretion

increase in the amount of CO₂ in their circulation and decreases the pH of their blood

carbs will produce more CO₂

women = 36.8

men = 40.5

standard basal conditions

Basal Metabloc Rate

the subject must not eat at least 12 hours prior to the test

the subject must be mentally and physically relaxed

the subject must not have a fever

the temperature of the room air must be comfortable (65-80 degree F)

BMR (+/- %) =measured value - predicted normal value
predicted normal value

1. muscular activity (exercise) - metabolic rate also remains elevated for up to several hours after exercise
2. ingested foods increase metabolic rate because of their specific dynamic action (SDA or thermic effect of food TEF)
3. environmental temperature - low temps, heat conserving mechanism activated, metabolic rate rises
4. sex (males have higher)
5. age (decreases with age)
6. emotional state (stress increases)
7. climate (high or low increase)
8. body temp (higher temp, higher MR)
9. pregnancy (increase MR)
10. menstural cycle (increase MR)
11. lactation (increase MR)
12. growth hormone (increase MR)
13. catecholamines (increase MR)
14. muscle mass (the greater muscle mass the greater heat production)
15. thyroid hormones (thyroxine) circulating - when one fasts for a prolonged period of time, thyroid hormone secretion decreses reducing metabolic rate

SDA

Specific Dynamic Action

Thermic Effect of Food

TEF

EPOC

Excess Post-Exercise Oxygen Consumption

the perent of the expired air that is oxygen

<20.93%

between 0.15 and 0.18

percent of expired air that is carbon dioxide

>0.03%

between 0.025 and 0.06

metabolic rate = roughly the same but the smaller person's was a little higher

heat production = larger person's was larger

nervous system and endocrine system

autocrine, paracrine, gap junctions

nerve cell

transmit impulses in order to pass info from one point to another

the junction between an axonal ending and another cell

where the nerve cell is transferred to the other cell via the release of neurotransmitters by axonal ending

neurotransmitters

brain and spinal cord

processes, analyzes, integrates and responds to info provided by the sensory neurons

transmit impulses away from the CNS to an effector organ

send info out of the spinal cord via the ventral root

the conduction of an electrical signal over long distances

"all or none" because of the either on or off status

initiated at an axon hillock or in a dendrite that traels to the soma and then down the axon to the end target

cardiac, skeletal and smooth muscle cells all have APs

"silent nerve" that is turned off

large concentration of Na outside and small concentration of Na inside

small concentrationg of K outside the cell and a large concentration of K inside

differences in concentration of charges between the inside and the outside

measured in volts (V)

millivolts (mV)

between -60 and -100 mV

the status quo potential of the "off" cell

Na channel opens, Na rushes into the cell (influx) via simple, passive diffussion

When Na moves across the membrane into the cell it causes the electrical potential across the membrane to be more postive (less negative)

K channels open slowly, K leaves the cell (efflux)

When K is leaving and Na channels are closed, there is a net movement of positive charges from inside to the outside of the cell, thus the membrane potential starts to become less positive (more negative)

brings membrane potential back towards resting potential

pump Na from inside to outside of the cell and move K back into the cell from the outside

occurring against [ ] graident --> requires energy in the form of ATP

3 Na for ever 2 K

ions against a [ ] gradient requires energy in the form of ATP

uneven exchange of positive charges is partly responsible for the relatively negative resting membrane potential

concentration gradient and electrical gradient

ex: K- electrical gradient favor K moving into cell, [ ] gradient favor K moving out of cell

the membrane potential wat which there would be no net movement of an ion because the electrical and concentration gradients cause an equal and opposite movement of the ion

Na = +60 mV

the membrane is more permeable to potassium and thus the membrane potential is closer to equilibrium potential for K (-90 mv)

When Na channels are open, the membrane is far more permable to Na and now the resting potential will move toward sodium's equalibrium

V = IR

blood pressure difference, blood flow, and resistance

movement of air through the airways of the lungs

once an AP is initiated in one region of the neurolemma (nerve cell membrane) it will cause an action potential in a neighboring region of the neurolemma

the stimulus will open the Na channels in the immediate area of the stimulus

As Na enter the cell the internal voltage of the cell is altered and the Na channels in teh adjacent area are opened

local current flow

contiguous conduction

1. diameter (affects the resistance of the nerve fiber) - the larger the diamaer, the more quickly the AP travels
2. presence or absence of a myelin sheath around the axon
3. temperature - low temps=slow conduction velocity

autoimmune disease characterized by destruction myelin in the CNS and eventually may damage the underlying nerves

slower AP propagation and wide range of symptoms related to neuronal dysfunction

the amount of neurotransmitter released by an axon terminal as a result of one AP

result in either a EPSP or an IPSP

1. increasing the frequency of neurotransmitter release by a given axon terminal
2. increasing the number of axon terminals that are releasing neurotransmitters

1. voltage (strength)
2. duration (length of time the voltage is delivered)
3. frequency (the number of times per second the pulse is delivered)

instrument that can record the potential changes by plotting variations in electrical potential against time

click "O" then enter to stimulate the neuron

the end of the absolute refractory period

and

the beginning of the absolute refractory period

the longest delay setting where no second action potential can occur, even with an extra strong voltage

and

begins as soon as the action potential begins to occur

specialized structures at the ends of afferent nerves and they recieve stimuli

receptors detectm the nerves transmit the info, and the CNS is responsible for the snesing or perception of this info

receptors detecting changes within the bodty

subdivides into visceroceptors and proprioceptors

mechanoreceptors

thermoreceptors

nocioceptors

electromagnetic receptors

chemoreceptors

osmoceptor

regardless of the type and strrength of stimulus applied to a given receptor, the sensation perceived when the receptor responds is always the same

the sensation evoked is that for which the receptor is specialized no matter how or where along the pathway the activity is initiated

each principle type of sensation

pain, touch, sight and sound

each has a discrete pathway to the brain

in order for a receptor to be activated, the stimulus must be higher than a certain minimal level

the threshold strength is lowest for the adequate stimulus and higher for the other types of stimulus

a change in potential

1. mechanical deformation
2. application of chemical to the membrane
3. change in the temp of the membrane
4. the effects of electromagnetic radiation on the receptor

differences in intensity of a given sensation are communicated in two ways:

1. frequency coding- changes in frequency at which action potentials are generated
2. population coding - changes in the number of receptors activated

a graphic presentation of the area in the sensory cortex dedicated to each part of the body

clearly displays the location and size of each site

located on the parietal cerebrum, just posterior to the central sulcus

info starting at the receptor and passing by way of an afferent nerve to the spinal cord or brain stem is recieved and where sensing or perception of the stimulus occurs

all areas of the body surface

1. the magnitude of cortical representation of the area on the body surface
2. overlapping sensory fields in the skin

the principle that connects the receptor site to its perception on the cortex

no matter where a particular sensory pathway is stimulated along its course to the cortex, the conscious sensation produced is referred to the location of the receptor

a segmental field of skin where each spinal nerve innervates at

maps used clinically to locate nerve lesions

branches of visceral pain fibers synapse with some of the same second order neurons that receive pain fibers from the skin.

when pain fibers of an organ are stimulated, action potentials signaling pain from the organ are conducted through some of the same neurons that conduct pain impulses from the skin

cutaneous receptors are rarely stimulated singularly

several different receptors are stimulated at the same time

if the stimulus strength remains constant and the stimulus is not removed, the receptor becomes increasingly less sensitive to the presence of the stimulus

the receptors at first responds at a very high impulse rate, then at a lower rate, until many of them no longer respond at all

receptors adapt very slowly and incompletely

ex: carotid sinus, muscle spindle, organs for cold, pain and lung inflation

the sensation percieved after removal of the stimulus

due to the receptor again discharging with removal of the stimulus

respond to changes in temp

cold receptors increase their discharge of impulses as their temp decreases, while warm receptors increase their firing rate as their temp increases

one's ability to discriminate the intensity of a stimulus is far greater at the low intensity level than at the high intensity level

gradations of stimulus strength are discriminated approximately in proportion to the logarithm of the stimulus strength

how the nervous system is able to discern stimulus strength over a tremendous range of intensities

emphasizes that the greater the background sensory stimulus, the greater the stimulus strength is in order for the brain to detect the change

Delta I/I

.

After sensory info enter the spinal cord via the dorsal roots, they may ascend the spinal cord through one of two alternate pathways located in the cord's white matter columns:

1. the dorsal-lemniscal system
2. anterolateral system

They come together at the level of the thalamus

a sensation that must be transmitted rapidly or that has fine gradations of intensity levels

limited to mechanoreceptive sensations (esp. joint sense, proprioreception, localized touch sensation, vibration)

includes the lateral and anterior spinothalamic tracts, transmits info more slowly than the tracts in the dorsal columns and allows for a less fine ability to discriminate the intensity of the stimulus

transmit a broad range of sensory modalities

inability to perceive peripheral sensory info as a result of nerve damage

ex: diabetic sensory neuropathy

pinna, the external auditory meatus (ear canal), and the outer surface of the tympanic membrane (ear drum)

collecting and transferring sound waves to the middle ear

contains 3 auditory ossicles:

malleus (hammer), incus (anvil), and stapes (stirrup)

function to transfer vibrations of the tympanic membrane to the inner ear

consists of 2 sensory receptors:

cochlea

vestibular apparatus

the sense organ for hearing

contains hair cells

compression and rarefaction

They are conducted and focused by the outer ear and cause the tympanic membrane to vibrate, which foreces the malleus to move. The malleus directly moves the inclus, which in turn moves the stapes. The stapes creates vibration on the oval window causing the generation of waves within the fluid of the upper compartment of the cochlea. The result in the vibration of the basilar membrane, causing the hair cells of the organ of Corti to move back and forth. The back and forth motion causes graded potential changes in the receptors at the same frequency as the transmitted sound waves. As the hair cells are depolarized, the auditory nerve is excited, sending receptor info along the auditory pathway to the auditory cortex in the temporal lobe of the brain.

1. conductive hearing loss
2. sensorineural hearing loss
3. central hearing loss

a loss of hearing acuity due to aging

caused by a loss of hair cells and decreased elasticity