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anatomy test 1
PART TWO
| Question | Answer |
|---|---|
| How does the myocardium receive blood? | -coronary arteries -a significant amount of the oxygenated blood that leaves the left ventricle through the aorta returns to the heart through the coronary arteries -they encircle the heart and rest in the atrial ventricular grooves |
| do arteries carry oxygenated or deoxygenated blood? | -carry oxygenated blood away from the heart - (with the exception of the pulmonary arteries which carry deoxygenated blood to the lungs) |
| do veins carry oxygenated or deoxygenated blood? | -carry deoxygenated blood towards the heart - (with the exception of the pulmonary veins which carry oxygenated blood from the lungs) |
| describe blood flow through the heart | oxygen poor blood from body- S and I VC- RA- TV- RV- PSLV- PA- lungs- PV- LA- BV-LV-ASLV-aorta- rest of body |
| how does the autonomic NS innervate the heart? | parasympathetic slows down the heart by releasing acetylcholine from the vagus nerve - sympathetic increases heart rate and contractility through norepinephrine release. |
| what does the SA (sino-atrial) node do? | - "primary pacemaker" located in right atrium -action potential is about 75 times/minute- sends impulse to both atria : contraction -it's large fibers = rapid speed of conduction ( the rate at which electrical impulses travel along nerve fibers_ |
| what does the AV (atrio-ventricular) node do? | -in right atrium, above the tricuspid valve -small fibers = slower conduction than SA node -may act as pacemaker if SA is damaged, but it would be at 40 bpm -would need artificial pacemaker to get to 75 bpm |
| tunica intima/ interna | - provides a smooth low-resistance surface that helps the blood move without friction -the endothelium rests on a basement membrane of elastic and dense connective tissue |
| tunica media | -relatively thick middle layer of smooth muscle and elastic connective tissue -plays role in blood flow and blood pressure, can be dilated or constricted by the autonomic nervous system |
| tunica externa/ adventitia | -outer layer of dense and elastic connective tissue with many nerve fibers -protects and reinforces the whole blood vessel |
| how do steroid hormones work inside the cell? | -they cross the plasma membrane via diffusion b/c they are nonpolar -diffuse into the cytoplasm (or directly into the nucleus) -bonds with receptor -forms active transcription (copying) factory -activate gene expression -new protein alters function |
| examples of steroid hormones | -glucocorticoids -mineralocorticoids -androgens, estrogens -progesterones (sex steroids) |
| what is the difference between autocrine, endocrine and paracrine signaling? | autocrine- chemical acts on the cell from which it came paracrine- the chemical signals nearby cells, a "local hormone" endocrine- hormone is secreted directly into the blood/bodily fluids |
| describe the events of the cardiac cycle | -one cycle is about .8 seconds of ventricular diastole and systole -1. passive ventricular filling and 2. atrial contraction = diastole -3. isovolumetric (volume remains same) contraction and 4. ejection =systole 5. isovolumetric relaxation = diastole |
| passive ventricular filling (diastole) | -after t wave, before p wave -blood enters relaxed ventricle -atrial ventricular valve is open -about 80% of blood flows directly to the ventricles due to gravity -semilunar valve closed |
| atrial contraction (diastole) | -SA node depolarizes and propagates, corresponds to p-QRS interval on EKG -remaining blood is pumped onto the ventricle -ventricular pressure increases |
| isovolumetric ventricular contraction (systole) | -ventricle contracts and pressure causes the atrial ventricular valves to close (s1 sounds) -aortic semilunar valve is still shut |
| ventricular ejection (systole) | -corresponds to the qrs-t interval on EKG -begins when ventricular pressure is greater than aortic pressure -semilunar valve opens -blood is ejected from ventricles |
| isovolumetric ventricular relaxation (diastole) | beings when aortic semilunar valves slam shut (s2 sound) -bicuspid and semilunar valves are closed, no blood added and no contraction occurs -ventricular pressure falls and becomes less than atrial pressure |
| what is orthostatic hypertension (OHT) | -a type of high blood pressure characterized by an increase in systolic blood pressure when transitioning from a seated or lying position to standing. |
| what is difference between preload and afterload? | preload (end diastolic volume)- the amount of blood filling the heart before it contracts, and that enters the ventricles after filling and contraction afterload- the pressure at which semilunar valves open (high afterload, blood pressure will be high) |
| what is normal vs abnormal bp? | normal systolic= less than 120 mmHg diastolic = less than 80 mmHg abnormal= higher than that |
| what structures/mechanisms prevent the back flow of blood? | the atrial ventricular and semilunar valves prevent the backflow of blood -the trabeculae carnae which are connected to the papillary muscles help keep the AV valves shut and prevent them from opening backwards to let blood back into the atria |
| what do the SA and AV nodes do? | The SA (sinoatrial) node generates an electrical signal that causes the upper heart chambers (atria) to contract. The signal then passes through the AV (atrioventricular) node to the lower heart chambers (ventricles), causing them to contract, or pump. |
| how does vessel diameter affect blood flow and vascular resistance? (Vascular resistance is the resistance that must be overcome for blood to flow through the circulatory system) what is the lumen of a blood vessel? | -less diameter means higher blood pressure and vascular resistance - more diameter means lower blood pressure and vascular reisstance -lumen= the open space in the middle where blood flows |
Created by:
emma.thornton