cardiovascualr challenges and research Flashcards
What change(s) in the structure and function of the heart are apparent in elite athletes trained for resistance (power) sports?
A Left ventricular wall thickness increased
B Left ventricular volume increased
C Maximum cardiac output increased
D Stroke volume at rest increased
A - left thickness increases
Healthy people don’t have a Change in CO
Thicker wall will increase contraction force but this means the volume is decreased
What changes in the structure and function of the heart are apparent in elite athletes trained for endurance sports? (Select any/all that apply)
A Cardiac output at rest is increased
B Heart rate at rest is increased
C Left ventricular volume is increased
D Left ventricular wall thickness is increased
E Stroke volume at rest is increased
C - left ventricular volume increased E- stroke volume increased
Healthy people don’t have a Change in CO but for long distance runner and fit people, their HR is low so that means their SV must be high
If SV is high then so is the ventricular volume
But as its endurance, the force of contraction/power isn’t necessary so the thickness of wall stays the same. Also if wall is thick ten volume would be low which can’t be the case
Which of the following manipulations or chemicals will cause an increase heart rate?
A Stimulating the vagus nerve
B Severing or damaging the vagus nerve
C The beta receptor antagonist Propranolol
D The muscarinic receptor antagonist Atropine
E The alpha adrenergic agonist Phenylephrine
B- damage vagus a PNS nerve D- atropine. Misvurince is PNS so antagonise will suppress the PNS
obviously vagus nerve is PNS so slows heart
C - antagonise beta will block the SNS
E - ALPHA acts on blood and smooth muscle and beta acts on heart
what feature of coronoary arteries means they can cause heart attack?
coronary arteries supply blood to heart but there are few connections (anastomases)
so if blocked, one patch of heart spasms
how does the electrical activity of the heart relate to the contractile behavior of the heart?
Electrical activity precedes muscle/contractile activity. Electrical activity is delayed AV node before being relayed at the bundle of His and conduct down the Purkinje fibres (etc)
what does the QRS complex on an ECG represent?
A depolarisation of atria
B depolarisation of ventricles
C repolarisation of ventricles
D conduction through AV node
E ventricular depolarisation and repolarisation
OPTION B
how does the heart act as a functional syncitium. How Does it communicate between cells
it would have gap junctions to allow action potential/electrical activity to propogate
> act as a single UNIT
stroke volume can be controled extrinsically and intrinsically, name some of these methods
EXTRINSIC: circulating hormones can alter calcium availability and hence the force of contraction (excitation contraction coupling)
E. G. Thyroid hormones have many cardiovascular effects to increase cardiac output!
INTRINSIC: stretching of the muscle means more powerful contraction
> this allows cardiac output to be controls
Which type of intercellular junction is most likely to exist in the endothelium of aorta?
Answer:tight and anchoring junctions
The endothelium of the aorta must have tight junctions between cells to stop leakage of blood. In addition, the aortic endotheliumstands on basal lamina, which is connected with the cell via anchoring junctions.
How does arterial pressure change with height(gravity)
I still don’t get wgy
Above the heart, arterial pressure decreases with height
Below the heart arterial pressure increases
Head - 60mmHg
Heaet - 90
Feet - 120
How can smooth muscle tone be altered?
control of vascular tone
Neurotransmitters and hormones
Physical factors - temperature and heat
Metabolism changes/chemical - H+, ppCO2
All to alter vasoconstrict/vasodilate which helps with the differential distirbution
How do veins maintain blood flow back to the heart whilst defying gravity?
Wrapped around arteries or wrapped around muscles when they contract
Skeletal muscles help prevent the pooling of blood
arteries pull and increase pressure+ SQUEEZE helping blood move past the vlaves
What do arteries do?
Act as a pressure reservoir to drive blood forward and can control the differential distribution of blood to where its needed!!
What do veins do?
Act as blood reservoir and move low oxygen, low pressure blood
need valves to ensure undirectionality of blood
what is cardiac output
cCO = SV X HR
volume of blood pumped by the heart per minute
athletes heart characterised by low heart rate and higher stroke volume
a low SV indicates poor cardia function
