Explain the functional structure of the heart
- Four-chambered muscle organ encased in a pericardiac sac
- Two atria, receive blood and two ventricles pump blood.
- Right atrium receives blood from superior and inferior vena cavas and the coronary sinus.
- Blood exits aorta
- Tricuspaid valve, right ventricle, and atria
- Mitral (Bicuspid) valve, left ventricle and atria
Define blood pressure, cardiac output and stroke volume
- Blood Pressure: The force of circulating blood on the walls of the arteries.
- Cardiac output - The amount of blood the heart pumps through the circulatory system in a minute.
- Stroke volume - the amount of blood pumped by the left ventricle of the heart in one contraction.
By what mechanism do pharmacological interventions alter blood pressure?
- centrally acting drugs decrease arterial pressure by decreasing systemic vascular resistance and cardiac output.
Detail how capillary blood flow increases by 15 – 20 times during high-intensity exercise.
- Increased number of blood vessels
- Capillary density is known to increase with endurance training,
Is it correct to assume that arterial blood is oxygenated and venous blood is deoxygenated? Explain your response.
Yes
• Which exercise type will see the greatest increases in blood pressure?
High intensity
- Aerobic activities such as swimming, cycling, and running put additional demands on your cardiovascular system
Outline how total peripheral resistance affects blood pressure during exercise.
- Blood pressure increases with increased cardiac output, peripheral vascular resistance, volume of blood, viscosity of blood and rigidity of vessel walls
Define the rate-pressure product
- and how is it calculated
- Rate pressure product is a measure of the stress put on the cardiac muscle based on the number of times it needs to beat per minute (HR) and the arterial blood pressure that it is pumping against (SBP).
- RPP = SBP x HR
List the four components of the cardiovascular system.
- Heart, Veins, arteries, blood
List the four main components to the conduction of cardiac impulse.
- The sino-atrial (SA) node.
- The atrio-ventricular (AV) node.
- AV bundle (Bundle of His)
- The Purkinje fibres
Relate the normal ECG waves to components of the cardiac cycle
P wave (atrial depolarization )
a QRS complex (ventricular depolarization)
and a T wave (ventricular repolarization)
the U wave ( Purkinje repolarization),
What area of the brain controls cardiovascular function?
Medulla oblongata
How would you explain the neural regulation of cardiovascular function during exercise?
The cardiovascular center is a part of the human brain found in the medulla oblongata, responsible for regulation of cardiac output
- also regulated by the PNS
Define anticipatory response to exercise
- When you are about begin exercising, your heart rate will likely increase before you begin moving. The phenomenon is called the ‘anticipatory rise’. The anticipatory rise is the mind’s response to the body’s need to prepare for exercise
Detail the role of chemoreceptors and baroreceptors in altering cardiovascular responses during exercise.
- The function of the baroreceptors is to maintain systemic blood pressure at a relatively constant level,
- Their function is to sense pressure changes by responding to change in the tension of the arterial wall. The baroreflex mechanism is a fast response to changes in blood pressure.
- Arterial chemoreceptor increases sympathetic vasoconstrictor outflow to muscle, and increases cardiac sympathetic activity to increase heart rate and contractility.
What causes heart rate to change during exercise?
- Increased stroke volume as your muscles need more oxxygen
Explain which factors may influence changes in cardiac output.
- heart rate and stroke volume
- blood volume reflexes, autonomic innervation, and hormones.
- Secondary factors include extracellular fluid ion concentration, body temperature, emotions, sex, and age.
- Contractility
• What does a plateau in cardiovascular response represent?
indicates that a steady state has been achieved
Define cardiovascular drift
- , the progressive increase in heart rate and decrease in stroke volume
• Provide an example of where cardiovascular drift may occur during exercise. What physiological factors may explain an associated reduction in exercise performance?
- Cardiovascular drift occurs when a person has a higher RPE (Rate of Perceived Effort); tThis creates a mental block that can inhibit performance greatly
- This results in a decrease in pulmonary arterial pressure and reduced stroke volume in the heart]. To maintain cardiac output at reduced pressure, the heart rate must be increased.
What are the layers of the heart
Epicardium - the outer layer.
Myocardium - the middle, muscular layer.
Endocardium - the inner layer.
