Which chamber of the heart pumps oxygenated blood to the body?
Left ventricle
Which type of blood vessel carries blood away from the heart?
Arteries
What is the term for heart muscle relaxation?
Diastole
What muscle contracts to allow inhalation?
Diaphragm
What gas do we inhale to stay alive?
Oxygen
What valve prevents backflow from the left ventricle to the left atrium?
Mitral (Bicuspid) valve
Blood returning to the heart enters through which large vessels?
Superior and Inferior Vena Cava
What heart sound is made when the AV valves close? (“Lub” or “Dub”?)
“Lub”
What small sacs in the lungs allow gas exchange?
Alveoli
What gas is exhaled as waste?
Carbon dioxide
Name the wall of tissue that separates the left and right sides of the heart.
Septum
What component of blood carries oxygen?
Red blood cells / Hemoglobin
What node acts as the heart’s natural pacemaker?
SA Node
What structure prevents food from entering the trachea?
Epiglottis
What controls breathing rate in the brain?
Medulla oblongata
What is the thick muscle layer of the heart called?
Myocardium
Which type of vessel is one cell thick to allow gas exchange?
Capillaries
Define systole.
Contraction of the heart chambers to pump blood
What are the smallest airways that lead to alveoli called?
Bronchioles
What happens to the diaphragm during exhalation?
It relaxes and moves upward
Trace the pathway of blood through the chambers of the heart starting from the right atrium.
Right atrium → Right ventricle → Lungs → Left atrium → Left ventricle → Body
Compare arteries and veins with 2 differences.
Arteries: thick walls, high pressure, no valves; Veins: thin walls, low pressure, valves
Place in order: AV node, SA node, Purkinje fibers, Bundle of His.
SA node → AV node → Bundle of His → Purkinje fibers
Trace airflow (start at nose, end at alveoli).
Nose → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli
Explain diffusion in gas exchange.
Oxygen & CO₂ move from high → low concentration across alveolar membrane