Exam 2 Class

Question 1

What is the resting potential of live heart cells?

dead?

Answer 1

most live cells have steady potnential of about -70 mV (energy used to maintain resting potential and used for little things like importing ions or glucose and secreting molecules) if dead membrnae potential leaks up to 0

Question 2

What is special about the excitable heart cells?

Answer 2

excitable cells- subset of cells that an adjust their permeability to ions based on membrnae voltage
like any cells, cardiac cells separate electrical charges across membranes but specialized pacemaker cells in heart swing their membrane potential rhythmically between -60mV and 0 mV (1% cell in heart: autorhythmic own intrinsic rhythm of shifts in membrane potential).

Question 3

What do the cardiac muscle cells do?

Answer 3

This signals cardiac muscles cells to respond with their own shift in membrane potential, and they then contract on a rhythm set up by pacemakesers (99%+ cells contractibile muscle).

Question 4

Describe the changes in structure of membrane proteins?

Answer 4

arm of amino acid might move change shape based on positive and negative charge around it with arms of things repelled by positive charges in the cells gate shutting or opens in resposne to channel changes no longer ahnging out at resting potntial leading to cascade of events with a set of ion channels moving in response to voltage.

Question 5

What kind of channels does the sinoatrial node have?

Answer 5

Sinoatrial node membrane has voltage gated potassium, calcium, and sodium channels

Question 6

What is bulimia?

Answer 6

binge on food and throw it up with throwing up pulls positively charged ions out of the stomach throwing up acid flushing posotively charged ions out of body and throwing off electrolyte balance leading to potassium imbalances affect heart rhymacy

Question 7

What is action potential?

Answer 7

reversal of membrane potential. starts at -40 mV

Question 8

What is pacemaker potential?

Answer 8

spacers between action potential with length adjusted and can change the slope and starting point adjusting time to reach action potneital threshold can drag out how far reaches and in between action potentials.

Question 9

What is the vagus nerve?

Answer 9

AKA (cranial nerve 10) goes to heart and slows heart rate with vegas nerve repeatedly slowing it down (runners and cyclists) releasing acetylcholine increase potassium permeability in SA node cells. when more time for potassium to leave cell the recovery period is longer

Question 10

What controls the heart?

Answer 10

Control and adjustments to mean arterial pressure- internal organs receive innervations or nerves throughout. From sympathetic (all internal organ- speeding things up going faster and makes things more intense fight or flight) and parasympathetic (connecting to same muscles but slowing things down rest and digest) branch with the innervation to the heart. intrinsic pumping of heart and arterioles can go on own with local propertie sof muscle and salivary gland can adjust functions with sympathetic and parasympathetic (off to the sides)

Question 11

What is pacemaker potential?

Answer 11

control heart rat eby adjusting length of pacemakers with slow inward leak stopping at -40mV opening of another kind of ion channel allowing calcium in.

Question 12

What is an action potential?

Answer 12

is a signal to cardiac muscle to contract occuring with fast increase and decrease sneding message to cardiac pacemaker cells.

Question 13

What is the spacing dependent on?

Answer 13

spacing of action potential dependent upon pacemaker potential to unfold and drift to -40 mV.

Question 14

What is short pacemaker potenaiL?

Answer 14

short pacemaker potential more permeable to potassium increasing heart rate by increasing number of action potentials squeezed in a minute brought by sympathetic stimulation decreasing permebaility of sinoatrial node to potassium

Question 15

how do you slow down the heart?

Answer 15

To slow it down using parasympathietic nervous system the potential will increase changing length f time for potassium to leave. vagus nerve from floor of brain.

Question 16

What do neurons do to affect this?

Answer 16

neurons in baroreceptor respond to stretch by creating an action potential increasing rate of firing of action ptentials signaling cardiac control center into the brainstem. increase rate of firing due to stretch with high blood pressure dong more stretch and there is an increase in the number of action potential to the brainstem

Question 17

What is low blood pressure?

Answer 17

low blood pressure- less stretch and fewer action potential to the brainstem

Question 18

What do the heart nerves do?

Answer 18

heart has nerves all over drip acetylcholine on heart on sympathetic nervous system and when on receiving end changes property of muscle such that at a given heart beat if it receives a certain mL it can generate more tension at fiber length.

Question 19

What is the equation for respiration?

Answer 19

Fuel (adjacent carbon molecules hold potential energy in their C-C bonds) + O2 to CO2 + H20 + energy re-packaged into ATP. die quickly within minutes, because loosing body weight in ATP a day

Question 20

What is the structure of ATP?

Answer 20

ATp- oxygen hogs all electrons from phosphate with it energetically favorable for phosphate groups to pop off with terminal phosphate popping off leaving and be added ot something else phosphorylating another molecule leaving ADP behind.

Question 21

What are carbohydrates?

Answer 21

Carbohydrates linked together to make long chains forming by combination of hydroxyl and hydrogen group when water excluded

Question 22

what is RER?

Answer 22

Respiratory exchange ratio (RER) CO2/O2. Glucose=1.0, fats

Question 23

What does anaerobic do?

Answer 23

free H+ ions from anaerobic respiration stimualtes pain receptors in muscle

Question 24

What happens in endurance exercise?

Answer 24

endurance excercise is high lactate threshold and good oxygen getting more endurance, thickening wall of left ventricle growing more capillaries, heart through training increase and decrease rate of pumping in a more quick manner with onset of excercise and then stops excericse and doesnt come down and increase number of enzymes to break down lactate reaching lactate threshold on the long races.

Question 25

what do electrons do?

Answer 25

elections are then passed to electron carriers in mitochondrial inner membranes with the final electron acceptor is oxygen.
final electron acceptor is oxygen and energy genrated by progressive falling of electrons is used to pump hydrogen across mitochondrial inner membrane. electrons are passively tuorn off acetlycol A creating 34 ATP.

Question 26

Where does fat go in system?

Answer 26

acetyl coa via beta oxidation

Question 27

Where do proteins go?

Answer 27

proteins can be used and generatie pyruvate or acetyl Coa inddirectly

Question 28

What is ventilation?

Answer 28

filling and emptying of lungs with air

Question 29

What governs the flow of air into and out of the lungs?

Answer 29

Flow of air in and out of lungs still governed by delta p(pressure difference in atmosphere vs. lungs)/R.

Question 30

What makes the delta p in the lungs?

Answer 30

with the container and thoracic cavity as the pump with it pressurizing air.

Question 31

how do you measure air pressure?

Answer 31

way of measuring air pressure measured by units of mmHg based on glass tube and dish of mercury based on any pressure exerted on the pool of mercury with air all around setup and exerting pressure on the walls of container and surface of mercury causing mercury up into tube and tube it vacuum not influenced by air pressure flowing up to a particular height and then somes- 760mm.

Question 32

What changes the pressure?

Answer 32

if the pressure that is atmospheric is 760mm, the pressure in the alveoi has to be either higher or lower than that otherwise there is no delta p. the pump works by chanigng the volume of alveoli can change indidivual volume of alveoli.

Question 33

How do alveoli change?

Answer 33

alveoli stretchy an dlined with fluid so oxygen and carbon dioxide can dissolve and transfer
pressure is inversely proportional to volume. if we can adjust volume we can change internal pressure int hat cavity. in alveolus if volume decreases pressure increases and converse is true.

Question 34

What is exhalation?

Answer 34

when you exhale your chest cavity constricts and your diaphragm comes up with overall volume going down so pressure in alveoli increase.

Question 35

What is the thorax?

Answer 35

Thorax was muscular pump changing shape and pressure. Muscle sheath in abdominal cavity and thoracic muscles across that hold in the lung diaphragm (convex) and when inhaling it is shaped a little more flat. sphenic nerve from brain changes compression rate

Question 36

What are the muscular structures of ribs?

Answer 36

two ribs right next to eachother sheet of muscle in beat them with short sheets connecting one rib to the next changing position of each other moving together and expanding apart

Question 37

What is the external intercostal?

Answer 37

when contracted, open up the thoracic cavity like an umbrella

Question 38

What is the internal intercostal?

Answer 38

decrease volume of the thoracic cavity. thus pressure goes up in the alveoli then that higher Delta P, If Palveloar goes up to 761 mm Hg, that is higher than pressure atmospheric, which is 760 mmHg having a delta P. diaphragm relaxes interval interconstal contact

Question 39

What occurs at inhalation?

Answer 39

At inhalation, the idea is to expand the volume of the chest cavity, external intercostal contract and diaphragm contracts, which increases volume in the thoracic cavity and moves it to open like umbrella, dropping pressure in the alveoli. with delta P moving air from atmosphere to alveoli opposed by resistance to airflow and other gunk if sick. phrenic nerve increase rate of firing if not enough oxygen is taken in

Question 40

What is intrapleural pressure?

Answer 40

Intrapleural pressure in pleural cavity is about 756 mmHg with a vacuum sucking the lungs up to the thoracic cavity and even as intraalveloar pressure rides up to down in compared to atmospheric pressure keeping close to that space. Intrapleural space keeping memmbrane sliding if pressure equalizes and lung collapses

Question 41

What happens when the lung collapses?

Answer 41

smooshed the lung because the delta P is lost creating a new trachea. with tube could suck the air out of the intrapleural space. constant positive pressure can cause daage to alveolar wall where the visceral pleura and ung collapses. with major resistance to flow is bronchioles. If alveloli not working the smooth muscle contract allowing air to go to other alveoli to gett more oxygen

Question 42

What is type II alveolar?

Answer 42

manufacture surfactant interfering with the surface tension of water not allowing it to make strong hydrogen bonds with surfacanat by apical cell with inside surface of cell and alevolis is wet with a mixture of water and surfactant need to dissolve oxygen into blood by keeping it moist.

Question 43

What is surfactant?

Answer 43

1 cell thick and really floopy so surface tension with hydrogen bonds in between and internal cohesion could be enough to cause alveoli to collapse the water will pull on itself compressing sphere allowing it to separate them and keep them infalted but so delicate and inflate. if no surfactant very difficult for individual to breath can be put in chamber to inflate them for them and manually inflating for long periods very difficult. surfactant manufactured around 8 months gestation and if born before that dealing with surface tension.

Question 44

What occurs in the alveolar?

Answer 44

macrophage eat phagoparticulates in inspired air. water in alveolar air displaces some atmospheric air no full oxygen and not full carbon dioxide because of dead space and so atmospheric air has more oxygen and less carbon dioxide than regular air and is not same gas concentration as outside air pressure.

Question 45

What is the dissolved component in blood like?

Answer 45

dissolved component available to perfuse but is not all of the gases carried in blood and usually carried bound to some sort of carrier

Question 46

What is Dalton’s Law?

Answer 46

idea that if fluid has pressure that overall pressure exerted by fluid on its container made up of component pressures of individual bits ex. if atmospheric air exerts pressure of 760 mmHg N2 79% of atmospheric air .79x760=600mmHg. O2 is 21% .21x760=160mmHg. >1% CO2=.03mmHg

Question 47

What are the concentrations of carbon dioxide in the body?

Answer 47

Carbon dioxide is sdissolved in plasma/red blood cells (10%), bound to hemoglobin (30%), locked into bicarbonate ion (60%)- enzyme called carbonic anhydrase. 90% of CO2 is carried and it cant be diffusing anywhere

Question 48

What is the concentration of oxygen like in the body an dhow is it bound?

Answer 48

oxygen can be dissolved in plasma/or cytoplasmm of rbc (1.5% dissolved contributing to partial pressure of O2. 98.5 O% is bound to hemogobin (enucleate, no nucleus). Oxygen continually popping off o hemoglobin carried ot tissues refreshing the dissolved compoentn all through the tissues and hemoglobin continually loaded up with oxygen through lungs. persistance of delta C thorughout tissues. hemoglobin sensing low PO2 unloading its O2 at low Po2 but it binds O2 at high PO2s.

Question 49

What is the structure of a hemoglobin molecule?

Answer 49

hemoglobin molecular made up of 4 globular proteins, with 4 nitrogen contianing rings with iron in the middle and 1 hemoglobin molecule. hemoglobin either fully loaded, or at low partial pressures fully unloaded.

Question 50

What is hemoglobin?

Answer 50

Hemoglobin massive submerged carrying capacity of oxygen as a gas and oxygen can leave or enter dissolved component be stored or liberated form hemoglobin with variety of oxygen levels in envronent giving a margin as a kind of buffer.

Question 51

Why is hemoglobin magical?

Answer 51

magic of hemoglobin is that its binding affinity for oxygen is well-tuned ot the partial presure of oxygen. hemoglobin will tend to unload oxygen where the delta c for oxygen is really great and so hemoglobi saturation the number of hemoglobin high as it enters tissue and loses it as leaving tissue dumping to dissolve component p o2 falls off slowly along length of capillary as hemoglobin unloads o2 keeping it higher for longer

Question 52

What are the concentrations of carbon dioxide like?

Answer 52

carbon dioxide simailar amount as oxygen but not as dramatic as 210 ml oxygen/L blood.

Question 53

What happens in carbon monoxide poisoning?

Answer 53

carbon monoxide 200x affinity for hemoglobin than oxygen does. carbon monoxide is odorlesa dn if adding to dissolved component. have to manufacture new red blood cells because you cannot get the carbon monoxide of the oxygen. with carbon monoxide bound to all homogoglobin only have dissolved oxygen takes a long time for brain to respond and only relying on so poorly soluble oxygen of 2.5 mlO2/L starving tissues as you wipe out hemoglobin

Question 54

What is the maintenance of the brain like?

Answer 54

Brain- your high maintenance friend. 2% body weight but 15% of cardiac output, 20% of body’s O2, and 25% of body’s glucose 10-15% minutes of no glucose is generally death. it primarily uses oxidative phosphorylation and without it nerve cells sodium potassium pump don’t work lose gradient and die.

Question 55

How does the brain form?

Answer 55

embryo forms from a flat sheet (before missed menstrual period) other animals form as circle. ectoderm and skin on top of embryo thickens (neuroectoderm) in a way that the thickening is what determines the anterior posterior axis of the embryo 3D shape changes based on growing. spckly bit with neural crest drip down and migrate into other areas of body forming other kinds of tissue (skull, teeth and melanin)

Question 56

Why is folic acid important?

Answer 56

folic acid allows the fusion of the neural tube with low folic acid there are birth defects of not forming neural tube. if doesn’t fuse at anterior end it is incompatible with life leaving open to amniotic and deteriorate (anencephaly lack of brain). spinabifada- neural tube at posterior end is compatible with life may not control legs and need assistance getting around or lower level of severity have dimple and no ille ffects.

Question 57

Why does the neural tue close and how does the brain continue to develop?

Answer 57

brain closed at one end-25 days shape change is due to differential change and curling i some areas of differential cell division. anterior end of tube, forebrain becomes larger and larger and larger dwarfing the back end of the brain

Question 58

What does the forebrain turn into?

Answer 58

telencephalon (cerebral hemispheres) and diencpahlon

Question 59

What does the midbrain turn into

Answer 59

cerebral aqueduct

Question 60

what does the hindbrain turn into?

Answer 60

pons, cerebelo, and medulla

Question 61

What is special about each persons brain?

Answer 61

exact pattern of hte wrinkles is not the same across everyone but it can be mapped generally across all people.

Question 62

What is the choroid plexus?

Answer 62

releasing cerebrospinal fluid sneaking out surface of spinal cord and surface of brain between skull and neural tissue and quantity of space occupying as well as in fourth ventricle and can enter systemic circulaiton to be destroyed by passing into sinus venous

Question 63

What is brain circulate like?

Answer 63

blood dumps into sinus (emty space) and drains into other veins and conveyed back to heart obvious where two cerbrosinous come together. otherwise jello mold with no integrity and is the same consistency of the cerbrospinal fluid

Question 64

What are the components of blood?

Answer 64

plasma and formed elements

Question 65

What is in the plasma components?

Answer 65

plasma composed of water, dissolved substances such as gases and protein hormones, and proteins such as albumen, firbinogen (clotting), and globulins (immune functions)

Question 66

What are the formed elements?

Answer 66

formed elements: erythrocytes/red blood cells (hematocrit test, platelets, and leukocytes/white blood cells.

Question 67

What is the CNS vulnerable to?

Answer 67

brain and spinal cord is vulnerable metabolically because of ion concentration, acid/base balance, and oxygen/glucose supply. It is also physically vulnerable because it is such a soft/squishy jello type tissue

Question 68

What are some protective measures?

Answer 68

blood-brain barrier, bone, and meninges

Question 69

What is the blood-brain barrier usually like and different with brain?

Answer 69

blood-brain barrier most places in body with pretty free exchange between vascular and interstitial compartments
but in the brain vascular compartment is much more segregated and not as wide open with interstitial and vascular have closed/tight gap junctions between endothelial cellsthanks to glial cells signals mainted by astrocytes to keep things out and protect neuronal function. Drugs are exceptions to the blood brain barrier making getting other drugs or brains tricky

Question 70

What is bone protection?

Answer 70

Bone in vertebrates: keep central nervous system in bony covering carnium/skull made from neural crest cells (much of it) perofrates to allow passage of nerves to the CNS (afferent nerve fibers goes at CNS). from CNS to periphery (efferent fibers- exit the CNS)
Vertebrae- flexible body column protecting spinal cord

Question 71

What are meninges?

Answer 71

three mother layers

pia, arachnoid, and dura mater

Question 72

What is the first layer?

Answer 72

pia mater (inner most layer next to brain and spinal cord)- laying over spinal cord like tights soft material tracing folds of brain

Question 73

What is the second layer?

Answer 73

layer thickness to it and the two surfaces are held apart by weby material running in between with inside trabeculae or webbiness spongy material

Question 74

What is the third layer

Answer 74

tough, outermost layer and is fused to bone on one side and arachnoid in the other. CSF flows within ventriclesleaving through 3 different prforations out of the ventricle to wash over surface of brain circulating over surface of brain in aracnoid mater across surface of brian and spinal cord.

Question 75

What are some problems with the brain?

Answer 75

If brain injury and swelling huge problem with no swelling for places to go and goes to foamen magnum to swell. Fluid buildup in skulls is bad. Spinal fluid leaks to the vascular and is drained. If bleeding can bleed into dura having a tar between dura and arachnoid (subdural hematoma) draining into space compressing brain tissue with bleed with sheering of blood vessels (usually passing fro skull to blood vessels) more common in individuals where the brain may be a little smaller than cranium.

Question 76

What is the choroid plexus?

Answer 76

Choroid plexus- cells of brain creating cerebral spinal fluid

Question 77

What happens if a person is shaken?

Answer 77

shearing from blood vessels across brain to swell causing swelling in brain. Alcohol abuse have brain that shrinks in size, demetia can also cause brian to shrink with more space between brain tissue and skull with vessels becoming more posisble to shearing and bleeds compressing brain tissue when smaller

Question 78

What is the vertebral column?

Answer 78

Vertebral column curved because bipedal. Line up centrum to centrum as weight bearing. Solid tube ends at natural waist with split knwon as cuadal quina as a horse tial from eleel of waist tail slititng na dmove out through perforations of pelvis to serve lower body

Question 79

What direction does which kind of nerves enter spine?

Answer 79

Nerves carrying info to spinal cord go in dorsally or into the top of the spinal cord

Question 80

What occurs in erection?

Answer 80

Nerves carrying info to spinal cord go in dorsally or into the top of the spinal cord
Erection and automatic peeing create hook in to brain from gray matter to white in spinal cord to override things that are reflexes.

Question 81

What percent of the brain is made up of neurons?

Answer 81

Neurons are 10% of the cells in the brain,

Question 82

What percentage of the body are glial cells? what is their function? what are the four kinds?

Answer 82

90% are glia, or supporting cells.

astrocyte, ependymal, microglia, and oligodendrocytes?

Question 83

What are astrocytes?

Answer 83

maintains the blood brain barrier thorugh its contact with endothelial cells. Absorbed used up neurotransmittrs in the brain like GABA-glutamate maintaining potassium balance and taking up potassium. Most common kind of glial cell

Question 84

What are ependymal cells?

Answer 84

cells that line the central canal in the spinal cord and lines ventricles in the brain. Also, they are the cells of the choroid plexus (makes CSF)

Question 85

What are microglia?

Answer 85

macrophages of the brain, if overactive correlated to neurodegenerative disease (alzheimers multiple sclerosis)

Question 86

What are oligodendrocytes?

Answer 86

aka Schwann cells in PNS wrap long axonal process of neuron forming fatty protective wrapper for neuronal projections called the myelin sheath.

Question 87

What are the functions of neurons?

Answer 87

Neurons are 10% of the cells in the brain- notification of change/new information or no change, transfer of information, initiates a response, specific recipient. Biochemical: ie. tagging a protein, electrical change of things across gradient leading to a shift in charge separation across a membrane

Question 88

What is the pyramidal cells from cortex?

Answer 88

Pyramidal cell from cortex (top of brain with laminar structure of different layers communicating across layers. Cell body has long process and then a bunch of anxon branches and dendritic branches with branches off cell body in all directions as well as on axon.

Question 89

Where do u receive information?

Answer 89

Receives information from dendritic processes cell processes at which inputs are received. - with bumps (dendritic spines) on dnedrites having particular kinds of transmembrane receptors concentrated called. Inputs processed form dendrites terminating on cell body itself

Question 90

What is a receptive field?

Answer 90

for a cell is defined by its dendrite branches. Another neuron will send an inut to dendrite with lots of connections in cortex

Question 91

Where are outputs?

Answer 91

Outputs processed along axon

Question 92

What do all cells have in common?

Answer 92

All cells that are alive separate charges across the cell membrane that is a stored of potential energy, which can be released under certain circumstances. For ex. Secretion of some hormones, import glucose against its concentration gradient such as the epithelium of the small intestine

Question 93

What are excitable cells?

Answer 93

A subset of cells that have membrane potential are “excitable’ meaning that you can transiently shift membrane potential in response to a triggering event rippling in response.

Question 94

What are four kinds of excitable channels?

Answer 94

mechanical, chemical, temperature, voltage

Question 95

What are mechanical channels?

Answer 95

mechanical deformation stretching or pressure on membrane allowing ion channel to respond to trigger of opening

Question 96

What are chemical channels?

Answer 96

chemical binding of particular molecule to emmbrane shifts potential called ligand gated protein channels receiving trigger that changes protein channel acetylcholine, sense of smell and taste

Question 97

What are temperature channels?

Answer 97

Temperature channel that opens in response to temperature

Question 98

What are voltage channels?

Answer 98

Voltage ion channel that opens in response to voltage

Question 99

What do all four channels have in common?

Answer 99

All reduce to shift in emmebrane potential and only brain can tell them apart?

Question 100

How do potassium and sodium channels work?

Answer 100

Potassium and sodium have voltage sensing area changing shape of channel influencing the gates on the channel. Sodium channel can have activation gate 1 open or have inactivation gate 2 shut so it can be in many morphologies. All potassium and sodium channels do not open at once. Potassium lag behind sodium channels with kinetics of voltage sensing linked can differ. Na+ swing gate shut slowly so cant open right away even if they get another signal meaning you cannot run action potential again cannot be them all together

Question 101

What are the action potentials like in neurons?

Answer 101

Action potential prpagates itself down the length of the axon, no retrograde or backwards transmission, with AP always the same shape.

Question 102

Describe the deoxy and oxyhemoglobin curve?

Answer 102

Oxy-hemoglobin (high on the y axis) and deoxy-hemoglobin (low on the y axis) curve same thing. If CO is on it it shifts very strongly to the left.
As concentration of molecule goes up it increases but has a really funky shape. Very limited point that has O2 if there is any little deficit into getting oxygen to alveoli immediately see a fall-off. Ability of molecule to bind oxygen increases as it binds. The drop off is around 60 meaning in real hemoglobin molecule can be 100% saturated with oxygen can have big iceberg and store not gonna lose all of it doesnt happen and isn’t physiological at the high end can be 100% saturated over wide range of lung efficiencies compensating for a time. Having a tolerance for variation of how much oxygen is in alveolar air as long as in range of 65-100 mmHg. In zone of 20-60 are the kind of partial pressures in the tissues and really low if excerising heavily and not that low if stagnant but hemoglobin is responsive ot a variety of low partial pressures. One-way response at high end and super sensitivie to low levels. Tissues at 30 but at back to lungs near alveoli totally load up and zoom up to 100% saturated with a very labile response to partial pressures of O2 making it suitable for loading up over a wide range but sensitive and willing ot unload in a low range. Any red blood cell has to encounter whole range as it goes to the lung and tissue.
Saturation incdicating number of hemoglobin carrying 4 things of oxygen, 75% means that ¾ of hemoglobin is completely saturated and half is completely unsaturated (deoxyhmeoglobin)
Hemoglobin saturdated by something else crunching the wuld have a lower saturation of PO2 would be lower line. High temperature, CO2, H+ high having bohr shift in high excercise changing binding for O2 having a rightward shift. Leftward shift temperature lower, CO2 lower

Question 103

What are the excitable cells?

Answer 103

Subset are excitable transiently influencing the membrane potential with ion channels responding to a trigger such as temperature, ligand, mechanical, and ovltage. Can change permeability to ions with channels opening in response to triggers contrasting ability to cell that is alive and has resting potential is intestinal epithelial cell exploiting the sodium gradient across memberane importing a little and glucose across membrane. Could respond by generating graded potentials (could be hyperpolarized big or long) or action potentials (hitting threshold and looks the same for all cell types)

Question 104

Describe the structure of the brain?

Answer 104

Forebrain one hemisphere and then other hemisphere, with a ligament the hard layer of meninges running between two hemispheres looking at how the brain is covered by meniges the skill is far away and on top of skull is skin and hair. Under skull have hard layer of connective tissue, the dura mater adhering ot the skull and so it splits and divides triangular in the center creating the dural sinus making venous blood. Under the dura is the arachnoid where the CSF circulates flowing out and around brain and outside is enclosed in there. Then there is a pia mater with a duct from inside tube of forebrain to the outside arachnoid.

Question 105

What tis the choroid plexus structure?

Answer 105

In ventricle the choroid plexus makes CSF and flows CSF down spinal cord and when it flows out of inside of ventricle and in upper spinal chord the duct (foramine or luscha on side or magendie) goes to the arachnoid and flowing outside of the brain and continous with the spinal cord. Having CSf on inside of cord and outside. Some arachnoid are projecting into pleural sinus and pushed into blood with no diffusion or exchange this is just outflow pipes to the blood. The CSF is constantly made but only 125 mL are circulated. Important in sleep