Packet 14: Circulation and Respiration
14-1
Aim: How does the structure of the heart relate to its function?
(A) FUNCTIONS OF THE CARDIOVASCULAR SYSTEM
 The cardiovascular system
__________________________________________________________________
__________________________________________________________________
 It functions like a network of highways—connects the muscles and
organs of the body through ____________________ that transport blood
 The cardiovascular system transports different kinds of molecules:
1. _________________________from digested food are
transported to all cells in the body
2. _____________________________ from the lungs
3. metabolic wastes, ________________________________
4. hormones, ___________________________________________
___________________________________________
5. distributes heat to maintain a ____________________________
________________________________________________
 humans and other vertebrates have closed circulatory systems—this
means that ___________________________________________________
________________________________________________________________
 the cardiovascular system consists of :
1. ______________________________
2. ________________________________________________________
3. _______________________________
(B) THE HEART
 the heart is made up of __________________________________ which
function to pump blood
 the heart has two separate circulatory loops
1. Pulmonary Circulation: right side—pumps
__________________________________________
(deoxygenated) blood through the pulmonary arteries to the
lungs
_________________________________________________________
_______________________________________--the oxygenated
blood is then returned to the left side of the heart
2. Systemic Circulation: left side—pumps
___________________________________________
(oxygenated) blood through the arteries to the tissues of the
body—oxygen poor blood is then returned to the right side of
the heart through veins
(C) CIRCULATION OF BLOOD
 The heart has a wall that divides the right and left sides of the heart
 The top of the heart is made up of the right and left
_____________________
 Atria: (singular—atrium) :_____________________________________
____________________________________________________________
 Below the atria are the ventricles
 Ventricles: ___________________________________________________
____________________________________________________________
 The heart contains a series of valves that prevent blood from moving
backward
 The path of blood through the heart is as follows:
1. _____________________________________: two large veins—
superior (above) and inferior (below)—that collect all of the
oxygen-poor blood from the body
2. the vena cavae empty blood directly into the
_______________________________________ of the heart
3. the blood from the right atrium goes to the
_______________________________
4. as the right ventricle contracts, it sends blood into the
__________________________________________________
5. the pulmonary arteries carry the blood to the
___________________________________________________where
oxygen is picked up and carbon dioxide is dropped off
6. the freshly oxygenated blood returns from the lungs to the left
side of the heart through the
_________________________________, which empty blood
directly into the ______________________________________.
7. From the left atrium, the blood is pumped into the
____________________________________________
8. The left ventricle then forcefully contracts sending the blood to
the _____________________________________
9. The aorta sends the blood to the ___________________________
________________________________________________________
(D) HEART CONTRACTION
 Contraction of the heart is initiated by a small cluster of cardiac muscle
cells called the sinoatrial node which is embedded in the upper wall of
the right atrium
 These cells acts as the pacemaker of the heart
 They fire an electrical stimulus in a regular rhythm that is followed by a
contraction
 On average heart contractions occur at a rate of about 72 times per
minute—when you sleep it decreases, when you exercise it increases
 The SA node is controlled by two sets of nerves and is influenced by
hormones, temperature and exercise