AP exam modules 1-4

Explain the problem of intercellular communication in a large multicellular human body and how Fick’s law of diffusion relates to this problem.

  As distance increases, ROD decreases via Fick’s law

  Give examples of where in the body the different mechanisms for intercellular communication are found.

a.      Paracrine – across synapse (Ach)

b.      Autocrine – self signaling (macrophages)

c.      Endocrine – hormones in bloodstream

d.      Gap junctions – Cardiac cells (coordination)

e.      Synaptic/neural – CNS/PNS, parasympathetic/sympathetic NS

  Describe the hypothalamic portal system and its importance.  Part of the description requires the definition of tropic (regulatory) hormones.

  The hypophyseal (hypothalamic) portal system is important for ensuring that hypothalamic regulatory hormones wont become diluted in circulation, and instead are more quickly transported to their target cells in the ant. lobe via the portal system

    Describe how hormones are controlled by neural stimulus, humoral stimulus, and other hormones. [epinephrine, insulin/glucagon, calcitonin/parathyroid hormone, and hormones regulated by the hypothalamus and anterior pituitary hormones are important examples]

a.      Neural

                                                    i.     Epinephrine – neural (adrenal medulla is signaled to secrete)

b.      Hormonal

                                                    i.     T3/T4 – hormonal (stimulated by TSH)

                                                   ii.     Rest of ant. pit hormones

c.      Humoral

                                                    i.     Insulin – (triggered by too much blood glucose conc.)

                                                   ii.     Glucagon – (triggered by too little blood glucose)

                                                  iii.     PTH – (triggered by too low blood calcium conc.)

                                                  iv.     Calcitonin – (triggered by too much blood calcium)

Evaluate how hematocrit changes with dehydration due to sweating, with dehydration due to diarrhea, with changes in altitude, and with volume expansion?

1. Diarrhea

   1. Both solute and water are lost

   2. Decrease in volume, same concentration

   3. Isotonic hematocrit (no net movement), no RBC vol changes

2. Evaporative loss (sweat)

   1. Water loss only

   2. Decrease in volume, increase in concentration

   3. Hypertonic hematocrit (move out), decrease in RBC vol

Identify the polypeptide chain and amino acid substitution associated with sickle cell?

GAG —> GTG (glutamic —> valine)

three phases of homeostasis

1. Vascular

   1. Endothelial contraction

   2. Endothelins stimulate vascular spasm and endothelial division

   3. Endothelial cells get “sticky” to each other and platelets

2. Platelet

   1. Platelet adhesion

   2. Platelet aggregation

   3. Platelet plug

   4. Platelets activate to stimulate above processes

3. Coagulation

   1. Clotting depends on presence of clotting factors

Identify the clotting factors that play important roles in the intrinsic, extrinsic, and common pathways of coagulation?

1. Ex: 3 —> 7 —> 10

2. In: 7 —> PF-3 —> 8 and 9 —> 10

3. Co: 10 —> prothrombin activator —> prothrombin —> thrombin —> fibrinogen —> fibrin (clot)

Identify the clotting factors that are produced by the liver?

ALL EXCEPT III and IV (ALL EXCEPT 3 and 4)

Identify the clotting factors that require vitamin K for their synthesis?

II, VII, IX, X (2, 7, 9, 10)

Identify the mechanism of vitamin K in producing clotting factors in the liver?

Enough vitamin K needs to be present for the liver to synthesize 4 clotting factors, which affect all pathways and therefore are necessary for clot

Identify the functions of all of the white blood cells.

1. Lymphocytes – protect against pathogens

2. Neutrophils – Engage in phagocytosis

3. Basophils – Releases heparin

4. Eosinophils – Fight worms

5. Thrombocytes – maintain hemostasis because there are lots of them

6. Monocytes – become macrophages

Identify mechanism by which the heart generates an automatic rhythmic beat (i.e., identify the ionic basis for the pacemaker potential in the SA nodal cells)?

HCN ion channels (“funny” ion channels)

Identify the ionic basis for the cardiac muscle action potential, the reason for cardiac muscle’s long refractory period, and the purpose of the heart’s long refractory period as it relates to the function of the heart as a pump?

1. Ion channels have a RMP of -90mv, meaning they are more permeable to K+ (K+ move out)

2. The long refractory period is necessary for passive filling of the ventricles, which enables the heart to “pump”, without this it would be in a continuous state of contraction

Identify the mechanisms for the AV delay and its purpose?

1. Smaller road means slower traffic, the AV delay is to allow ventricles to fill with blood

2. AV node has smaller diameter than SA, slower conduction, and less gap junctions

Correlate the events of the ECG to the events occurring in the heart’s electrical conduction system?

1. P wave – atria depolarizes

2. QRS complex – ventricles depolarize

3. T wave – ventricles repolarize

4. P-R interval – from start of atrial depolarization to start of ventricular depolarization

5. Q-T interval – time it takes for the ventricles to undergo a single cycle of depolarization and repolarization

Identify the importance of the anatomical arrangement of the bundle branches and why it important that depolarize begin at the apex and “move” upward?

Blood is like toothpaste (“stroke volume”) contraction begins @ apex to push the most blood possible superiorly

how does the baroreceptor reflex work

increased pressure on sinus = increased AP via CN IX = cardioinhibitory stim, cardioaccelerator inhibit, vasomotor inhibit = parasymp tone stim, symp tone inhibit = HR decrease, vasodilation = TPR decrease = CO decrease = MAP decrease

how does the baroreceptor reflex work if clamps are placed below the carotid sinus?

clamp causes decreased pressure on sinus = decreased AP via CN IX = cardioinhibitory inhibit, cardioaccelerator stim, vasomotor stim = parasymp tone inhibit, symp tone stim = HR increase, vasoconstriction = TPR increase = CO increase = MAP increase

what happens to flow when vessels are in parallel

total flow is less than individual resistances, parallel vessels always increase flow

mechanisms of blood doping

uses EPO secreted by kidney in order to stimulate RBC prod. in RBM to increase hematocrit

compare vein and artery structure

A. There are an artery and a vein of equal overall diameter.  Which vessel would have a relatively larger lumen?

B. There is an artery and a vein of equal overall diameter. Which vessel would have a thicker tunica media?

C. Which tend to have valves?

D. What vessel has greater compliance?

E. Which vessel has a greater abundance of elastic connective tissue?

F. Which vessel serves as a pressure reservoir?

G. Which vessel serves as a volume reservoir?

H. Most of a person's resting blood volume occupies the

I. Which vessel is under the greatest pressure?

A. vein

B. artery

C. vein

D. vein has higher compliance

E. vein has more connective tissue

F. artery

G. vein

H. veins

I. artery

Compare the relative leakiness of the three different types of capillary? 

continuous - least leaky

fenestrated - somewhat leaky

sinusoid - very leaky

what are the two cranial nerves associated with the baroreceptor reflex?

glossopharyngeal (CN IX) and vagus (CN X)

Why does epinephrine at this concentration and dosage cause an initial decrease in mean arterial pressure (MAP) that is then followed by an increase in mean arterial pressure?

The initial decrease in MAP is mediated by the action of epinephrine on ______ adrenergic receptors of arterioles supplying the skin and skeletal muscles.

The later increase in MAP is mediated by the action of epinephrine on _______ adrenergic receptors of arterioles supplying the skin and skeletal muscles.

One can infer from the data that because there is an initial decrease in MAP in response to epinephrine that epinephrine has _______ affinity for beta-2 adrenergic receptors than for alpha-1 adrenergic receptors.

beta 1, alpha 1, greater

what kind of relationship do epinephrine and thyroid hormone have?

permissive relationship

where is vitamin D3 found?

the kidney

what clotting factor starts the extrinsic pathway?

factor III (tissue factor)

which clotting factors are mutated in a person with hemophilia (inability to clot)?

factors 8 and 9

what ion is involved in coagulation phase of hemostasis?

Ca++

what are the 2 types of hemoglobin?

alpha and beta hemoglobin

during which phase of the cardiac cycle do voltage gated Na++ channels open?

cardiac cycle phase 0

what voltage is present during the S-T segment of an EKG (and any “segment”)

all “segments” have a voltage of 0

are the AV and SL valves open or closed during “ISOvolumetric contraction”

AV and SL valves are closed

what is the small blip in artial pressure in the cardiac cycle known as?

the “A wave”

what valve’s closure corresponds with the 1st heart sound?

AV valve closure

what valve’s closure corresponds with the dicrotic notch event?

Aortic valve closure

what does atropene block (turtle heart)

atropene blocks ACh from MUchR receptors

does the phosphorylation of Ca++ ion channels via protein kinase A increase or decrease Ca++ concentration inside the cell?

increase Ca++ conc.

what converts angiotensin I to angiotensin II?

ACE

what converts angiotensinogen to angiotensin I?

renin

The cross-sectional area of the aorta is greater than that of the combined cross-sectional area of the capillaries.

A. true

B. false

B. false (there are lots of capillaries!!)