Cardiovascular System Flashcards
Is the blood in the aorta, left ventricle, and pulmonary artery oxygenated or deoxygenated ?
Aorta: oxygenated
Left ventricle: oxygenated
Pulmonary artery: deoxygenated
What occurs between the alveoli and capillaries?
Gas exchange
Which part of the brain has a role in the control of the heartbeat and how are message passed from this part of the brain to the heart?
Part of the brain: medulla oblongata
Type of message: nerve
What normally prevents the membranes of the alveoli form sticking together during expiration?
The secretion of fluids in the inner surface of the alveoli
Which chamber of the heart has the thickest walls?
Left ventricle
When intense physical activity is anticipated, which factor in the blood will increase the frequency of sinoatrial signals to heart muscle?
Epinephrine
What is the role of type 2 pneumocytes
To increase surface tension
Which feature maintains a high concentration gradient of gases in the ventilation system
Thin-walled alveoli
Which of the following describes arteries?
They have thick muscular walls
Which muscles contract to cause air to pass into the lungs though the trachea
External intercostal muscles and diaphragm
What is a role of the pacemaker or SA node?
To originate excitation in myogenic muscles
What feature of alveoli adapts them to efficient gas exchange?
A dense network of capillaries surrounds them
Capillaries surround the alveoli in the lungs. Which pair of statement correctly describes the concentrations of oxygen and carbon dioxide in the lungs
Oxygen: higher in the alveoli
Carbon dioxide: higher in the capillaries
How are the insides of alveoli prevented from sticking together?
Method of prevention: surfactant
Produced by: type 2 pneumocytes
List the the locations of chemosensors that detect changes in CO2 concentration in the blood
carotid artery aorta
Explain how the brain is involved with increases in respiratory rates
The respiratory control centre in the medulla oblongata responds to stimuli from chemoreceptors in order to control ventilation
- Central chemoreceptors in the medulla oblongata detect changes in CO2 levels (as changes in pH of cerebrospinal fluid)
- Peripheral chemoreceptors in the carotid and aortic bodies also detect CO2 levels, as well as O2 levels and blood pH
During exercise metabolism is increased, which results in a build up of carbon dioxide and a reduction in the supply of oxygen
- These changes are detected by chemoreceptors and impulses are sent to the respiratory control centre in the brainstem
- Signals are sent to the diaphragm and intercostal muscles to increase the rate of ventilation (this process is involuntary)
- As the ventilation rate increases, CO2 levels in the blood will drop, restoring blood pH (also O2 levels will rise)
- Long term effects of continual exercise may include an improved vital capacity
State the name of the enzyme in red blood cells that convert CO2 to a more soluable form
carbonic anhydrase
Explain the events of the cardiac cycle including systole, diastole, and heart sounds
The cardiac cycle describes the series of events that take place in the heart over the duration of one heart beat
- It is comprised of a period of contraction (systole) and relaxation (diastole)
Systole
- Blood returning to the heart will freely flow from the atria to the ventricles as the AV valves kept open by the pressure in the atria
- The sinoatrial node (pacemaker) receives signals to fire when the ventricles are almost full (~70%)
- The contraction of the atria (atrial systole) causes blood to fill the ventricles to the maximum
- The signal from the SA node is transferred to the AV node and then via Purkinje fibres to cause the delayed contraction of the ventricles
- As the ventricles contract, the increase of pressure in the ventricles closes the AV valves, causing the first heart sound (‘lub’)
Diastole
- The increased pressure causes the semilunar valves to open and blood to flow away from the heart
- As the blood flows into the arteries, the pressure falls in the ventricles
- This causes some arterial back flow, which closes the semilunar valves and causes the second heart sound (‘dub’)
- When the pressure in the ventricle drops below the pressure in the atria the AV valves open and the cardiac cycle can repeat
Explain how the structure of the artery allows it to carry out its function efficiently
- Thick wall to withstand high blood pressure
- Many muscle fibers to help pump blood
- Narrow lumen to maintain high pressure
- No valves as pressure is high enough to prevent back flow
- Thick outer layer of collagen to give strength
An adaptation of people who live permanently in high altitude areas
They have more red blood cells/hemoglobin/higher lung capacity
State possible cause of the curve shifting from myoglobin to hemoglobin
Decrease in pH levels
Outline the events that occur within the heart that correspond to the QRS complex
- The QRS complex represents depolarization of the ventricles (i.e. ventricular contraction), triggered by signals from the AV node
Describe the medical response to ventricle fibrillation
Using a defibrillator, which can be used to electrically restart the heat to a normal cardiac cycle and offset ventricle fibrillation
List two factors that are possible causes of CHD and explain what is occurring in the blood vessels
- ) sedentary lifestyle
- ) smoking
- Due to the sedentary lifestyle, fat deposits block the arteries and diminishes the diameter of the artery walls from pumping blood across the heart.
