Human Psychology Midterm 2

Which is TRUE about the function of the aortic semilunar valve

It prevents the backflow of blood into the left ventricle during ventricular diastole.

The majority of ventricular filling occurs while

both the atria and ventricles are in diastole

Which of the following statements concerning the period of isovolumetric ventricular contraction is true ?

The ventricles are completely closed chambers

What part of the conductive system of the heart directly delivers the action potential to the ventricular muscle cells or fibers?

Purkinje Fibers

The pacemaker of the heart is normally what structure ?

sionatrial node

Which statement is TRUE ?

SA node cells egin to depolarize very quickly after the end of the previous action potential

The QRS complex in an electrocardiogram best represents

depolarization of the ventricles

Contractile myocytes in the ventricular myocardium have two sources of Ca2+ for myocyte contraction, the sarcoplasmic reticulum and the extracellular fluid

True

Calcium induced Ca2+ release (CICR) is a property of cardiac muscle cells

True

What structure within the intercalated disk allows an action potential to travel from one cardiac myocyte to another?

Gap junction

Which valves are open during ventricular ejection ?

Both, aortic and pulmonary semilunar valves

Cardiac output is always greater than venous return

False

Which of the following is correct

CO= SV x HR

An increase in parasympathetic activity will cause a decrease in CO by directly causing a decrease in ventricular myocyte contractile strength

False

An increase in sympathetic activity will:

An increase in cAMP which in turn increases the rate of the pacemaker potential

When acetylcholine binds to the muscartinic acetylcholine receptor at the SA node cells it causes potassium channels to open which in turn slows down the rate of the pacemaker potential.

True

The Frank-Starling law of the heart basically states that if there is an increase in EDV the ventricular myocardium will be stretched more than normal resulting in a greater strength of ventricular myocyte contraction which in turn causes an increase in SV

True

The type of receptor found in the carotid body that detects blood pressure is known as a

Baroreceptor

Which formed element of blood is associated with blood clotting ?

Platelet

Hematocrit is the number of Leukocytes in circulation

False

Functions of the respiratory system include

regulation of blood pH, protection against microbes, making sounds used for speaking

The region of the airways where gas exchange occurs is called

the respiratory zone

During inspiration and normal tidal breathing, the dimensions of the thoracic cavity

increase due to contraction of the diaphragm

Sufactant...

decreases surface tension, and is secreted by Type II alveolar cells

Air flows into the lungs when

alveolar pressure is lower than atmospheric pressure

When Vanessa is breathing at rest, her ventilation rate is 15 breaths/min, her tidal volume is 600 mL and dead space volume is 150mL. Vanessa's Alveolar Minute Volume is

6,750 ml air/ min

When Vanessa begins exercising, her ventilation rate increases to 25 breaths per minute, and ventilation volume increases to 800 mL, and dead space volume is 150 mL. Vanessa's Minute Volume is

20,000 ml air/ min

If a student inhales as deeply as possible and then blows the air out until they cannot exhale any more, the total volume of air that they expelled is their ?

Vital Capacity

What is the normal partial pressure of oxygen in the pulmonary artery ?

40mm Hg

In which form is most of the carbon dioxide in blood transported as

Bicarbonate ions in plasma

Which of these would tend to cause an increase ventilation

lower than normal pH in CSF

During normal tidal breathing expiration is driven by activation of the internal intercostal muscles and the abdominal cavity to decrease the volume of the thoracic cavity

False

The Carotid Body oxygen sensing cells (Glomus cells) respond to a decrease in O2 levels in the blood and send sensory signals to the Medulla Oblongata and Pons Respiratory center which then causes

an increase in ventilation

Central chemoreceptors in the Medulla directly respond to increases in CO2 in the CSF and send sensory signals to the Respiratory control center to increase ventilation

False

Arterial O2 levels are directly detected by central chemoreceptors

False

Which of the following would cause an increased ability for hemoglobin to bind to oxygen?

an increase in blood pH

Gas exchange between the alveolar lumen and the blood plasma occurs across which cells ? (not including the red blood cell)

Type I alveolar and endothelial cells

How many cell membranes must oxygen cross as it crosses from the alveolar lumen to bind to Hemoglobin (Hb)

5

The volume of air that remains in the lung after a forced expiration is known as the expiratory reserve volume.

False

During inspiration the pressure in the thoracic cavity is increasing

False