Lab 13: Circulatory and Respiratory

Question 1

What does the blood pressure depend on?

-4

Answer 1

• volume of blood present
• size of the blood vessel
• rate of blood flow
• any resistance to blood flow

Question 2

cardiovascular center

Answer 2

• located in medulla oblongata
• Receives Input from
• Sensory receptors
• Higher brain centers

• Output from autonomic nervous system.

• Sympathetic cardiac acceleratory nerves:
• Parasympathetic cardiac inhibitory nerves:

Question 3

hormones for regulating blood pressure

• function
• which ones

Answer 3

• Function: altering heart function, blood vessel diameter and adjusting total blood volume.
• epinephrine and norepinephrine

Question 4

How does the hearts rythmic functions work

Answer 4

• Autorhythmic Fibers: set fundamental rhythm (self-excitable)
• can spontaneously depolarize and act as pacemakers.

Question 5

Cardiac excitation pathway

Answer 5

• Sinoatrial Node –> Atrioventricular (AV) node –> AV Bundle or Bundle of His –> Right and left bundle branches –> Purkinje Fibers –> cover inner surface –> wave of depolarization over outer surface –> ventricles contract

Question 6

Electrocardiography

Answer 6

• measurement and analysis of currents associated with heart activity
• extremely important in the diagnosis of abnormal cardiac function

Question 7

Electrocardiogram

Answer 7

• ( ECG or EKG).

* The recording of the electrical changes of the heart

Question 8

P wave

Answer 8

• Upward (positive) deflection
• atrial depolarization.
• Duration = 0.08 second (range 0.06 - 0.12 sec)
• Amplitude = not greater than 0.3 millivolts.

Question 9

QRS complex

Answer 9

• series of negative and positive deflections
• ventricular depolarization.
• Repolarization of atria
• Duration = 0.08 second (range 0.06 - 0.10 sec)
• Amplitude R wave = not over 2.5 millivolts.

Question 10

T wave

Answer 10

• positive deflection
• ventricular repolarization.
• inverted (negative) T wave is abnormal.
• Duration = 0.16 second
• Amplitude = 0.3 millivolts (highly variable)

Question 11

Abnormalities of the deflection waves

Answer 11

useful in detecting myocardial infarcts or problems with conduction system of heart

Question 12

Measurement of Frog Heart Activity

Answer 12

Epinephrine

• heart rate: increase
• contraction strenth: increase
• this chemical simulated control by sympathic

Acetylcholine

• heart rate: decrease
• contraction strenth: decrease
• this chemical simulated control by parasympathic

Question 13

Frog Experiment: 4°C Ringer’s solution vs. 37°C

- Would you expect this treatment to increase or decrease the heart rate?

Answer 13

4°C Ringer’s solution

• Decrease in heart rate/strength
• Cold decreases muscle activity, ion moves slowly, increase viscosity or cytoplam, decrease activity of protein channels

37°C Ringer’s solution

• Increase in heart rate/strength
• Heat increases muscle activity and ion movement

Question 14

pulse

• define
• rate

Answer 14

• alternating surges of pressure in an artery that occur with each contraction and relaxation of the left ventricle
• averages 70 - 76 beats per minute in the resting state.

Question 15

An instrument called a _____ is used to measure arterial blood pressure.

Answer 15

sphygmomanometer

Question 16

In clinical terms, when discussing “blood pressure”, it means…

Answer 16

• arterial blood pressure.

Question 17

Systolic v. Diastolic pressure

Answer 17

Systolic pressure - maximum pressure in the arteries during ventricular contraction (systole).

Diastolic pressure - minimum pressure in the arteries during ventricular relaxation (diastole).

Question 18

why do blood pressure and pulse rate changed when posture changed from reclining to immediately standing up. What role do baroreceptors play?

Answer 18

• When reclining, no gravity effects, more blood pooling at the heart already so decrease in blood pressure and pulse rate.
• Drop in blood pressure as soon as you stand then it will be restored. Upon standing, initial heart rate increase due to decrease in venous return (as you’re trying to maintain blood flow to heart), blood pools in legs.
• Baroreceptors relax to increase blood pressure and heart rate and return to normal

Question 19

Explain the changes in blood pressure and pulse rate immediately after exercise and once exercise has ceased for 5 minutes.

Answer 19

• After exercise, vasodilation occurs in skeletal muscle and constricts everywhere. Increased Venus return, squeeze veins, increased heart rate, increased cardiac output due to increased oxygen demand of skeletal muscle.
• After 5 minutes, venous return back to normal, resting levels established as demands have been met

Question 20

How would you expect a trained athlete to differ from an “unfit” person with respect to the effects
of exercise on pulse rate and blood pressure?

Answer 20

Athletes would have less on an increase in heart rate and blood pressure with exercise. Athlete heart size can be bigger and resting heart rate is lower.

Question 21

Factors other than posture and exercise also influence heart rate. What would be the effect of drinking a cup of a highly caffeinated beverage on pulse rate?

Answer 21

Caffeine is a stimulant and would increase heart rate

Question 22

What is hypertension?

Why is prolonged hypertension dangerous?

Answer 22

Prolonged higher than normal arterial pressure

Can lead to stroke and renal problems

Question 23

Explain the effect of “hardening of the arteries” on the diastolic and systolic components of blood pressure?

Answer 23

• Increase systolic blood pressure because artery is unable to expand with surge of blood.
• Decrease diastolic blood pressure because artery is unable to recoil (diameter is increased)

Question 24

Valsalva maneuver

Answer 24

• increases intrathoracic pressure
• can be used to demonstrate the effect of thoracic pressure changes on venous blood pressure
• Procedure:
take a deep breath, and mimic the motions of exhaling forcibly without actually exhaling. In reaction to this, the glottis will close and intrathoracic pressure will increase.

Question 25

blood pressure within veins is readily affected by external factors

Answer 25

• muscle activity
• gravity
• pressure changes occurring in the thorax during breathing

Question 26

How does this value for Valsalva maneuver compare with the venous blood pressure measurement computed for the relaxed state?

Answer 26

venous blood pressure increased during valsalva maneuver

Increased intrathoracic pressure, decreased venous return to heart because of pressure gradient. More blood stays outside thoracic area and pools in periphery, therefore veins in arm stay distended.