Circulatory System

Question 1

Blood Pathways

Answer 1

1. Systemic Pathway: to/from body cells
2. Pulmonary Pathway: to/from lungs
3. Cardiac Pathway: to/from heart muscles

Question 2

Functions

Answer 2

Transport, defense, repair, body temp regulation, maintaining water levels

Question 3

Red Blood Cells (Erythrocytes)

Answer 3

Specialized with hemoglobin (has iron) that carries oxygen (sometimes carbon dioxide); biconcave disk to increase surface area for gas exchange

Question 4

White Blood Cells (leukocytes)

Answer 4

Defends against bacteria and viruses, increases when body is fighting infection

Question 5

Platelets (thrombocytes)

Answer 5

Reacts with clotting factors to form temporary clots (thrombus) to prevent blood leakage

Question 6

Plasma

Answer 6

Clear, yellowish fluid (55% of total blood volume, made up of 92% water) - carries blood components, salt, enzymes, water, clotting factors, and maintains fluid balance

Question 7

Counting Blood Cells

Answer 7

Low RBCs - leads to anemia (from bleeding or iron-defiency) –> feels tired
High WBCs - body is fighting infections –> symptom is leukemia (cancer of bone marrow and blood)

Question 8

Arteries

Answer 8

Carries oxy blood from heart to body cells (exception - pulmonary artery: carries deoxy blood from heart to lungs) –> disorder: aneurysm (rupture)

Question 9

Artery Structure

Answer 9

Large, muscular, thick-walled with small inner diameter (three layers of tissue) and very elastic - contraction of heart = arteries slightly expand = your pulse

Question 10

Veins

Answer 10

Carries deoxy to heart from body cells (exception - pulmonary vein: carries oxy blood from lungs to heart) - skeletal muscle contractions help move blood (against gravity)

Question 11

Vein Structure

Answer 11

Large, thin-walled (middle layer isn’t as thick), less elastic, large inner diameter (lower pressure), with valves

Question 12

Capillaries

Answer 12

Microscopic, one cell thick (inner diameter < 7 μm) that connect arteries and veins - low pressure, blood cells single file for gas exchange/nutrient-waste exchange

Question 13

Vasoconstriction

Answer 13

Nerve impulses cause smooth muscle in arterioles to constrict - narrows vessel diameter (occurs when cold - keeping heat)

Question 14

Vasodilation

Answer 14

Nerve impulses cause smooth muscle in arterioles to relax - increase vessel diameter (occurs when warm - loses heat to environment)

Question 15

Systolic Pressure

Answer 15

Pressure in blood vessels when heart beats (contracts and empties blood)

Question 16

Diastolic Pressure

Answer 16

Pressure in blood vessels when heart rests between beats (relaxes and fill with blood)

Question 17

Normal Blood Pressure

Answer 17

120 mm Hg / 80 mm Hg - measured in milliters of mercury

Question 18

Factors in Blood Pressure

Answer 18

Related to distance from heart (higher in arteries than veins - inner diameter)
1. Demand on heart for blood (e.g. higher during exercise)
2. Vasoconstriction –> more blood left in artery –> increased blood pressure

Question 19

Hypertension

Answer 19

High blood pressure

Question 20

Heart Node

Answer 20

Specialized type of tissue that acts as muscle and nervous tissue

Question 21

Heart Beat

Answer 21

Set by natural pacemaker - sinoatrial (SA) node located where vena cava enters right atrium. When nodal tissue contracts, sends nerve impulses through heart walls, triggers atrioventricular node to do same (helps power cardiac cycle)

Question 22

Heart Sounds

Answer 22

Sound of heart contracting and valves opening/closing produces “lubb-dubb”; abnormal heart sound (“whoosh”) = heart murmur

Question 23

Electrocardiogram Waves

Answer 23

P wave: atrial contraction
QRS wave: ventricular contraction
T wave: signals ventricles have recovered
Flat line: no heart contraction (no activity)

Question 24

The Heart

Answer 24

4-chambered double pump

Question 25

Right Side of the Heart

Answer 25

Receives deoxy blood from body via superior and inferior vena cava, pumps blood to lungs via pulmonary artery
(pumps blood to pulmonary circuit)

Question 26

Left Side of the Heart

Answer 26

Receives oxy blood from lungs via pulmonary vein, pumps blood to body via aorta
(pumps blood to the systemic circuit)