Week 6 "Overview of the cardiology system" Flashcards
What are the 4 types of vessels in the cardiovascular system?
Buffer vessels - aorta, large and middle sized arteries
Resistance vessels - small size arteries and arterioles
Metabolic vessels- capillaries
Capacitance vessels - veins
What mechanical factors are behind blood pressure?
Cardiac output (CO) Total peripheral resistance (TPR) BP= CO X TPR
What are the pressures within the vascular system for RV LV Aorta and Vena cava
RV - 15-30
LV 100-140
Aorta- 100-140
Vena Cava- 5
What are the features of the Buffer vessels that allow them to achieve their purpose?
aorta, large and middle sized arteries - tries to maintain blood pressure during systole and diastole. It achieves this through internal elastic membrane and large muscular base.
What are the features of the resistance vessels that allow them to achieve their purpose?
small size arteries and arterioles - provides structure to carry blood at high pressure- muscular walls
What are the features of the metabolic vessels that allow them to achieve their purpose?
capillaries - thin walls to allow for efficient diffusion. Large surface area as millions of capillaries.
What are the features of the capacitance vessels that allow them to achieve their purpose?
veins - stores lots of blood ready to be used by the heart if needed. (flexible)
What is systole
myocardial contraction - ejection of blood from the cardiac chamber
What is diastole
myocardial relaxation - filling the chambers
What is cardiac output?
CO= SV X HR SV = blood volume ejected from each ventricle during contraction.
What is Starlings law?
Starlings Law- describes the relationship between ventricular filling in terms of LVEDV (left ventricular end diastolic volume and stroke volume.
“when more blood stretches the ventricles, the ventricles contract more powerfully to pump out more blood”
The heart pups the same volume of blood out - that comes in. this occurs independent of neural or hormonal control.
What is the baroreflex?
The baroreflex or baroreceptor reflex is one of the body’s homeostatic mechanisms that helps to maintain blood pressure at nearly constant levels.
What are baroreceptors?
Stretch sensitive mechanoreceptors
Where are baroreceptors located?
Aortic arch and the carotid sinuses
What are examples of Sympathetic stimulation in the heart.
Increase in HR
Increase in SV
Increase in Resistance
Vasoconstriction
What are examples of Parasympathetic stimulation in the heart.
decrease in HR
decrease in SV
decrease in Resistance
Vasodilation
How do the lengths of Parasympathetic and Sympathetic fibres compare?
Parasympathetic- preganglionic = longer postganglionic = shorter Sympathetic - preganglionic = shorter postganglionic = longer
What neurotransmitters are used for PNS and SNS preganglionic neurons?
All preganglionic neurons release ACh (Acyetlcholine) onto nicotinic asetylcoline receptors (nACHRs)
Post ganglionic however
Sympathetic - noadrenaline
Parasympathetic - ACh
What are some features of a nicotinic receptor?
- Ionotropic (result in direct ion flow)
2. They are all excitatory
What are some features of a Muscarinic receptor?
- Can be excitatory or inhibitory in action
- Parasympathetic
- Use a G-Protein effect (secondary messengers)
- Effects on heart glands eyes GI lungs
What is Adrenergic nerve cell?
A nerve cell that uses adrenaline/ noadrenaline acts as a neurotransmitter.
(Sympathetic)
Symptoms - increase HR, BP, resp, shunting of blood away from GI functions, dilated pupils
What is a Cholinergic nerve cell.
A nerve cell that uses Acetylcholine (ACh) as a neurotransmitter.
(parasympathetic)
Decrease HR, BP, resp, constricted pupils
What are the three types of shock?
- Hypovolemic- loss of blood volume
- Distributive- Excessive blood vessel dilation in the wrong places (not distributing well)
- Cardiogenic- Heart output issues
- Obstructive- Clots as well as cardiac tamponade.
