Chapter 21 Circulation

Question 1

Open Circulatory System

Answer 1

Fluid is called hemolymph or interstitial fluid. hemolymph is pumped into body cavities known as sinuses.

Question 2

Arthropods have

Answer 2

1. Jointed appendages
2. Segmentation (head, throax, abdomen)
3. Hard chitinous exoskeletons
4. Bilateral symmetry
5. Complete digestive tracts
   Open circulatory system

Question 3

Arthropods examples

Answer 3

Insects, lobsters, crayfish, spiders, and scorpions.
Exoskeletons that are hard and do not expand. Periodically they molt. Enzymes partially dissolve the old exoskeleton.
Open circulatory system.

Question 4

Mollusks

Answer 4

Oysters, clams, octopuses and squids. Most secrete hard CaCO3 shell.
Open circulatory system.

Question 5

Closed circulatory system

Answer 5

Blood is confined in continuously connect walls of heart and vasculature. Annelids and all vertebrates have close systems.

Question 6

Arteries

Answer 6

Usually high in O2, blood is under high pressure. Carries blood away from the heart.

Question 7

Resistance is highest in the

Answer 7

Arterioles than in any part of the systemic circulation. Resistance is vital to blood flow regulation.Large diameters offer very little resistance to flow.

Question 8

Capillaries

Answer 8

Smallest blood vessels; single layer of squamous epithelium. Thin walls allow for O2 and nutrient exchange. Speed of blood is slowest. Largest cross sectional area in any part of the circulatory system. Capillaries converge to the venule.

Question 9

Veins

Answer 9

High in CO2, thinner walls, less smooth muscle and less elasticity than arteries.
Carries blood to the heart. Many veins have valves to prevent backward blood flow. Blood pressure is lowest here.

Question 10

More fluid leaves the capillaries than returns to them

Answer 10

Any excess is collected and returned to the venous circulation by the lymphatic system.

Question 11

of Heart chambers for organisms

Answer 11

Mammals (man) and birds: 4 chambered heart
Reptiles: 3 chambered heart (crocs and alligators have 4)
Amphibians: 3 chambered heart
Fish: 2 chambered heart

Question 12

Heart terms basic

Answer 12

Atria: Upper Chamber
Ventricle: Lower chamber
Superior Vena cava: Brings blood low in O2 to the right atria from the upper body
Tricuspid Valve: Between right atria and right ventricle
Mitral Valve: Between left atria and left ventricle

Question 13

Semilunar Valves (Pulmonary valve and Aortic)

Answer 13

Aortic valve separates left ventricle and aorta (largest artery). Keep blood from flowing backward.
Pulmonary valve separates right ventricle from pulmonary artery.

Question 14

Lup Dup

Answer 14

Heart sounds due to closing of the valves.
Lub: 1st sound; AV valve closes (tricuspid and mitral).
Dub: 2nd sound, Semilunar valves close (aortic and pumonary).

Question 15

Papillary Muscles

Answer 15

Muscles in the ventricles that help stabilize heart valves.

Question 16

Chordae tendineae

Answer 16

Fibrous strings attached to the cusps on the ventricular side, originating from the papillary muscles.

Question 17

Systolic pressure

Answer 17

Arterial blood pressure when ventricles contract (120mmHg)

Question 18

Diastolic pressure

Answer 18

Arterial blood pressure when ventricles relax (80mmHg)

Question 19

Cardiac Muscle

Answer 19

Usually mononucleated, striated, loads of mitochondria

Question 20

Intercalated discs

Answer 20

Transverse bands that separate adjacent ends in cardiac muscle fibers; low resistance so impulses can move rapidly.

Question 21

SA Node, Pacemaker

Answer 21

Found in the RA, generates electrical impulses analogous to nerve cells.

Question 22

Heart’s Electrical System

Answer 22

SA node, AV node, His purkinje system

1. SA Nodes sends out an impulse; both atria contract
2. SA -> AV node - slight delay at the AV node to allow time for atrial systole before ventricles contract. Once the impulses reach the His bundle and purkinje fibers the ventricles contract.

Question 23

Heart Electrical Path

Answer 23

SA node - > AV anode - > Bundle of His and Purkinje Fibers