Repetition cardiovascular system Flashcards
Formula for 1 heart cycle?
R1-R2 / [mm/s] = [s]
Formula for heart frequency?
Heart cycles pr. minute [BPM]
60s / time for one heart cycle [s]
Formula for stroke volume?
EDV - ESV = mL
volume after diastola - volume after systola
Formula for cardiac output?
amount of blood pushed out from LV –> systemic circulation
stroke volume x heart frequency = [mL]
3 ways to change the blood pressure?
cardiac output
heart frequency, stroke volume
constriction of vessels
Which two systems can regulate BP?
Nervous system and humoral system
Which hormone regulates BP and is influenced by both the nervous system and the humoral system?
ADH/Vasopressin
Where is ADH produced and how does it work?
Produced in hypothalamus, secreted by neurohypophysis. Retention of water in distal tubules of kidneys, constrictions of arterioles.
Agonist of ADH?
Aldosterone
What is Aldosterone and where is it produced?
Mineralocorticoid, produced in zona glomerulosa in adrenal cortex.
How does aldosterone work?
By sodium (Na+) conservation in distal tubules and collecting ducts of kidneys. Reabsorbtion of Na+ and excretion of K+
What id indirectly influenced by Aldosterone?
Water retention… retention of Na+ also holds back water
Antagonist of Aldosterone?
ANP –> atrial natriuretic peptide
Produced in right atrium of heart.
What is the RAS system?
renin, angiotensin system
How does RAS work?
angiotensinogen produced by liver –>angiotensin I (by renin)–>angiotensin II (by ACE) The hormones then provide vasoconstriction by muscle contractions of vessel walls
What does RAS stimulate?
Aldosterone production
What is SAS?
Sympato Adrenal System
How does SAS function?
Adrenal gland produce epinephrine and nor-epinephrine which stimulates the sympathetic and para-sympathetic nervous system.
How does SAS work to increase BP?
Epinephrine stimulates fight or flight response and increase bloodflow to muscles and incr. cardiac output and blood sugar. It binds to alpha or beta receptors. Alpha in vessels –> vasoconstriction
Beta in heart –> incr. cardiac output
How can we change heart frequency?
Emotional state, limbic system
What is the basic regulatory system?
Consist of medulla oblongata, pons, (brainstem) and midbrain. Responsible for basic functions and regulation of homeostasis.
What is formatio reticularis?
A branching of nerve fibres and nuclei in medulla oblongata,connected to the basic regulatory system.
What are reflexes, and how can they regulate heart frequency?
By two antagonical heart rate controls:
Baroreceptors and Bainbridge reflex
What are baroreceptors?
are sensors located in the blood vessels of all vertebrate animals. They sense the blood pressure and relay the information to the brain, so that a proper blood pressure can be maintained
What are bainbridge reflexes?
Also called atrial reflexes, is an increase in heart rate due to an increase in central venous pressure. Increased blood volume is detected by stretch receptors located in both atria at the venoatrial junctions.
How is the Frank Starling law?
Greater strenght = greater contractions
What are the vasodilators of endothelial cells?
Nitric oxide Prosta cyclins (susp. stability also)
How can vessels be local regulators?
They regulate bloodflow according to the needs of the organs they interact with.
Antagonist of nitric oxide?
Endothelin, produced by endothelial cells, vasoconstrictor.
Functions of pre-capillary spinchters?
Capillariea have only one layer of endothelial cells, no smooth muscle layers.
Spinchters control the bloodflow into the capillary beds.
