Biology Of Organisms Chapter 42

Front 1

Gastrovascular cavities

Back 1

bodies being only two cell layers thick, diffusion is optimal in trans-porting nutrients throughout the organism.
Example: cnidarians, platyhelminthes

Front 2

Open circulatory system

Back 2

one or more hearts pumps hemolymph into sinuses surrounding organs; body movements squeeze sinuses, assisting in circulating hemolymph
Example: arthropods, most mollusks

Front 3

Closed circulatory system

Back 3

one or more hearts pumps blood into vessels which branch into smaller and smaller vessels; blood never leaves the vessels
Example: earthworms, cephalopods, and vertebrates

Front 4

Open v. Closed Circulatory Systems

Back 4

Open: requires less energy in operation and maintenance; also, provides support during molting

Closed: more efficient at material transport; most highly developed in vertebrates

Front 5

Vertebrate Circulation - Fish

Back 5

1. One ventricle, one atrium
2. Gill & systemic circulation
3. Blood moves slowly
4. Two capillary beds where blood pressure drops

Front 6

Vertebrate Circulation - Amphibians

Back 6

1. One ventricle, two atria
2. Pulmocutaneous & systemic circulation
3. Double circulation
a. O2 poor blood to lungs, skin
b. O2 rich blood to body

Front 7

Vertebrate Circulation - Reptiles

Back 7

1. One ventricle, two atria
a. Partial second ventricle
2. Pulmonary & systemic circulation
3. Double circulation
a. Less mixing of O2 rich/poor blood

Front 8

Vertebrate Circulation – Mammals, Birds

Back 8

1. Two ventricles, two atria
2. Pulmonary & systemic circulation
3. Double circulation
a. Left side O2 rich blood
b. Right side O2 poor blood
4. Supports endothermicity

Front 9

Cardiac cycle

Back 9

one complete cycle of pumping and filling the heart

Front 10

Systole

Back 10

contraction, pumps blood

Front 11

Diastole

Back 11

relaxation, fills with blood

Front 12

Cardiac output

Back 12

volume of blood the left ventricle pumps per min.
a. Avg. stroke volume = 75 mls/contraction
b. Avg. cardiac output = 5.25 L/min

Front 13

Atrioventricular (AV) Valves

Back 13

located between each atrium & ventricle

Front 14

Semilunar valves

Back 14

located at two exits of heart (aorta & pulmonary artery)

Front 15

Sinoatrial node

Back 15

sets rate and timing at which all cardiac muscle cells contract (rt. atrium)

Front 16

Atrioventricular (AV) node

Back 16

relay which insures the ventricles contract after the atria (0.1 sec - btw. rt. atrium & rt. ventricle)

Front 17

Heart murmur

Back 17

problem in which blood squirts back through a defective valve

Front 18

Three Layers of Vessels

Back 18

Outer - connective tissue with elastic fibers
Middle – smooth muscle with elastic fibers
Inner – endothelium
a. Arteries have thick outer/middle layers
b. Capillaries have only endothelium

Front 19

Blood Flow

Back 19

As diameter of vessels decreases, velocity of blood flow increases
a. Total cross sectional area of capillaries causes blood flow to decrease - more capillaries than larger vessels

Front 20

Blood pressure

Back 20

hydrostatic pressure that blood exerts against the walls of vessels to propel blood
a. Greater in arteries than veins
b. Peripheral resistance
c. Gravity (neck length)

Front 21

Blood pressure

Back 21

Humans – head = 0.35m, 27 mm Hg
Giraffe – head = 2.5 m, 250 mm Hg
Dinosaurs – head = 10 m, 760

Front 22

Blood return

Back 22

assisted by rhythmic contractions of smooth muscles in walls of vessels and skeletal muscles squeezing surrounding vessels in limbs

Front 23

Capillary function

Back 23

blood flow to capillaries is irregular as blood is diverted from one area to another
a. Materials move across capillary walls by exo/endocytosis, osmosis, or through gaps in between cells

Front 24

Blood Composition and Function

Back 24

1. Plasma - liquid matrix with cells in suspen-sion (55% blood composition; 90% water)
2. Serum – plasma without clotting factor

Front 25

Plasma Substances

Back 25

a. Electrolytes – help maintain osmotic balance of blood; buffer blood to pH 7.4
b. Nutrients
c. Proteins
d. Hormones
e. Respiratory gases
f. Metabolic wastes

Front 26

Erythrocytes (RBC’s)

Back 26

a. Function: transport O2
b. Small (7 – 8.5 µm in diam.)
c. Most numerous (25 trillion/5L)
d. Contain hemoglobin (Hb)
e. Lack nuclei & mitochondria (mammals); generate ATP by anaerobic metabolism
i. 250 million molecules Hb/RBC
ii. Each Hb binds 4 molecules O2
iii. Each RBC carries 1 billion molecules O2

Front 27

Leukocytes (WBC’s)

Back 27

a. Function: defend against pathogens
b. Large (10 – 20 µm in diam.)
c. 25 - 50 billion/5L (increases during infection)
d. Nucleated; 5 different types

Front 28

Platelets

Back 28

a. Function: blood clotting
b. Fragments of cells (2 – 3 µm in diam.)
c. 750 – 1,750 billion/5L
d. Lack nuclei

Front 29

Blood clot

Back 29

self-sealing components of blood to stop bleeding; triggered by injuries

Front 30

Fibrinogen

Back 30

inactive clotting factor

Front 31

Fibrin

Back 31

active clotting factor

Front 32

Platelets

Back 32

incorporated to plug bleed

Front 33

Thrombus

Back 33

formation of a clot inside blood vessels in absences of injury

Front 34

Embolus

Back 34

traveling clot

Front 35

Hemophilia

Back 35

genetic mutation that effects any step of the clotting process resulting in excessive bleeding from even minor injuries

Front 36

Pluripotent stem cells

Back 36

source from which cellular elements develop
a. Ability to differentiate into any blood cell type
b. Found in marrow of ribs, vertebrae, sternum, and
pelvis

Front 37

Erythropoietin (EPO)

Back 37

hormone which stimulates the production of RBC’s
a. RBC’s turn over every 3 – 4 months
b. Reduction in O2 triggers EPO synthesis (negative feedback mechanism)
c. Alternative to steroids

Front 38

Leukemia

Back 38

cancerous line of stem cells that overproduce WBC’s
a. RBC stem cells are crowded out
b. Treatment: destroying bone marrow and restocking it with noncancerous stem cells (30 cells required to repopulate)

Front 39

Cardiovascular disease

Back 39

disorders of heart and blood vessels; accounts for ½ of all US deaths
Causes: Genetics, Smoking, Sedentary lifestyle, High animal fat diet, High cholesterol

Front 40

Artherosclerosis

Back 40

hardening/narrowing of arteries

Front 41

Hypertension

Back 41

high blood pressure

Front 42

Heart attack

Back 42

death of cardiac tissue due to prolonged blockage of one or more coronary arteries

Front 43

Stroke

Back 43

death of nervous tissue due to blockage/rupture of one or more arteries in the head

Front 44

Gas exchange

Back 44

uptake of O2 from and dis-charge of CO2 into the environment
1. Supports ATP production during respiration
2. Water (aquatic animals) and air (terrestrial animals) are sources of oxygen

Front 45

Respiratory medium

Back 45

O2 (oxygen)
1. Higher concentration of O2 in air than water
- molecules diffuse more easily through air than water (less energy required)

Front 46

Respiratory Surface

Back 46

1. Thin and moist with a large surface area
2. Gas exchange occurs by diffusion
3. Larger in endotherms than ectotherms due to metabolic activity

Front 47

Gills

Back 47

out-foldings of the body’s surface, suspended in water

Front 48

Ventilation

Back 48

aquatic organism’s increase of water flow over the gills

Front 49

Countercurrent exchange

Back 49

opposite flow of blood in gills to direction of water passing over gills
a. Removes 80% of O2 from H2O
b. Dumps CO2 at same time

Front 50

Trachea

Back 50

branching system of air tubes throughout an insect’s body
a. Finest branches extend to almost every cell
b. Efficient in small insects, but larger insects must ventilate
c. Trachea open to outside

Front 51

Lungs

Back 51

restricted to a specific region, using the circulatory system to expand functions
a. Found in spiders, terrestrial snails, and ter-restrial vertebrates

Front 52

Breathing

Back 52

alternate inhalation/exhalation of air; ventilates lungs

Front 53

Diaphragm

Back 53

sheet of skeletal muscle that increases lung volume when contracted