Human biology chapter 10
Hemoglobin acts as a buffer because ________.
protons released by the dissociation of carbonic acid bind to hemoglobin, preventing large swings in blood pH
Path of air
Air enters throughout the nose or mouth... air travels down the trachea and then enters the bronchi... air travels down smaller and smaller bronchioles... air reaches small sacs called alveoli
From which structures do oxygen molecules move from the lungs to the blood?
Alveoli
Which statement about carbon dioxide transport is FALSE?
An increase in the number of hydrogen ions increases the pH of the blood.
Key events in gas exchange
Breathing moves air in and out of the lungs... oxygen diffuses from alveoli in the lungs into the capillaries... oxygen enters red blood cells where it binds to the protein hemoglobin... oxygen diffuses from the blood to the body's tissues and carbon dioxide diffuses from the tissues to the blood... carbon dioxide leaves the body when we exhale.
Carbon dioxide transport
Carbon dioxide is released from the mitochondria... carbon dioxide diffuses into a capillary.... carbon dioxide is carried to the lungs... carbon dioxide diffuses into an alveolus... air exits through nose or mouth
In the blood most of the oxygen that will be used in cellular respiration is carried from the lungs to the body tissues _____.
Combined with hemoglobin
Which statement is correct?
In the blood, oxygen is bound to hemoglobin, a protein found in red blood cells.
Oxygen transport
Oxygen diffuses from the alveoli into surrounding capillaries... oxygen enters a red blood cell... oxygen binds to a molecule of hemoglobin... oxygen is carried through blood vessels to a capillary... oxygen diffuses from the body's tissues.
Which of the following happens when the CO2 level in the arterial blood increases?
The hydrogen ion concentration of the cerebrospinal fluid will increase, stimulating the medulla oblongata to increase the rate and depth of breathing.
True or false. When discussing breathing, we can say that air enters the lungs because the diaphragm contracts and in the process, oxygen passes into the alveoli and then down its concentration gradient from an alveolus to the blood. When we breathe out, the diaphragm relaxes and carbon dioxide passes down its concentration gradient from the blood to the alveolus and then out of the lungs.
True
Which of the following statements about oxygen transport is FALSE?
Under normal circumstances, about 50% of the oxygen is unloaded at the cellular level.
By picking up hydrogen ions, hemoglobin prevents the blood from becoming too _____.
acidic
Respiratory centers in the brain that regulate breathing are primarily stimulated by ________.
an increase in the level of CO2 in the blood
Most carbon dioxide is carried from the body tissues to the lungs _____.
as bicarbonate ions (HCO3 -)
One's bronchi and bronchioles constrict in response to minor triggers, severely restricting airflow and making breathing very difficult. This describes ________.
asthma
Most of the oxygen transported in the blood is ________.
bound to hemoglobin within red blood cells
Across which vessels does most internal respiration (the exchange of gases between the blood and tissues) occur?
capillaries
During an inhalation, the diaphragm moves ________.
downward
What type of respiration occurs in the lungs?
external respiration
The lower respiratory tract is responsible for ________.
gas exchange in the alveoli
Oxyhemoglobin is ________.
hemoglobin with bound oxygen
Hemoglobin
is a protein that can bind four molecules of oxygen
Venous blood ________.
is transported by pulmonary arteries to the lungs
After blood becomes oxygenated,
it returns to the heart, and is then pumped to body cells.
Carbon dioxide diffuses from the blood into the alveoli when the PCO2 of the alveoli is ________.
lower than the PCO2 of the blood
Tidal volume is ________.
the amount of air respired during restful, relaxed breathing
During inhalation,
the diaphragm and rib muscles contract
The interface between the air and the blood is composed of ________.
the epithelial cells of the alveolus, the extracellular fluid, and the capillary wall
Congestive heart failure affects lung function because ________.
the left side of the heart fails and blood backs up into the pulmonary vessels
Carotid and aortic bodies monitor ________.
the level of O2 in the blood
Inspiration occurs as ________.
the volume of the pleural cavity increases