Please enable JavaScript.
Coggle requires JavaScript to display documents.
CH:42 & 44 (Circulation and Gas Exchange (42.1 Circulatory systems…
CH:42 & 44
Circulation and Gas Exchange
Transfer of substances between animal and surroundings
Transfer: nutrients, O2, CO2, waste products
Unicellular: direct exchange with external environment
Multicellular:
Respiratory system
Circulatory system
42.1 Circulatory systems link exchange surfaces with cells
Diffusion
: random thermal motion of liquid, gases or solid
Difference in concentration result in net movement
slow process and occurs over small distance
Adaptation
simple body plan
Cnidarians and flatworms
#
cell direct contact with environment
each cell can exchange materials
complex body plan
a circulatory system
system move fluid between cell's immediate surroundings and the body tissues
above exchange occur over short distance
Gastrovascular cavity: the distribution of substances throughout the body and in digestion
more elaborate branching pattern
flat body optimizes exchange by increasing surface area and decreasing diffusion distances
Open and closed circulatory systems
3 basic components
A set of interconnecting vessels
A muscular pump- Heart
A circulatory fluid
open circulatory system
the circulatory fluid called hemolymph
Contraction of the heart
: hemolymph through the circulatory vessels into interconnected sinuses, spaces surrounding the organs
Relaxation of the heart
: draws hemolymph back in through pores
closed circulatory system
a circulatory fluid called
blood
hearts pump blood
into large vessels, into smaller ones, infiltrate the tissues and organs.
chemical exchange
occurs between the blood and the interstitial fluid and, between the interstitial fluid and body cells
Circulatory systems in vertebrate
cardiovascular system: heart and blood vessels
Blood vessels
Arteries: carry blood AWAY from the heart
arteries branch into
Arterioles
Capillarie:
microscopic vessels with thin, porous walls.
capillary beds:
network of capillarie
Veins
: carry blood TOWARD the heart
Venules
: capillaries converge into
muscular chambers in heart
Atria: receive blood entering the heart
Ventricles: responsible for pumping blood out of the heart
Single circulation: blood travels through the body and returns to its starting point in a single circuit
EX: sharks, rays, bony fishes
Double circulation: two circuits of blood flow
Pulmonary circuit
: gas exchange takes place in the lungs
Pulmocutaneous circuit:
gas exchange takes place in capillaries in both the lungs and the skin.
Systemic circuit
: the left side of the heart pumping O2 blood from the gas exchange tissues to capillary beds in organs and tissues
42.2 Double circulation in mammals
Mammalian Circulation
Blood begins its flow with the right ventricle pumping blood to the lungs
In the lungs, the blood loads O2 and unloads CO2
O2 rich blood heart enters the heart at the left atrium
the aorta provides blood to the heart through the coronary arteries
Blood returns to the heart through the superior vena cava
Vena cava flow into the right atrium
Cardiac cycle: the heart contracts and relaxes in a rhythmic cycle
STSTOLE: the contraction of heart
DIASTOLE: the relaxation of heart
HEART RATE: the number of beats per minute
STROKE VOLUME: the amount of blood pumped in a single contraction
CARDIAC OUTPUT: the volume of blood pumped into the systemic circulation per minute
ATRIOVENTRICULAR VALVE: lies between each atrium and ventricle.
SEMILUNAR VALVES: located at the two exits of the heart
Maintaining the heart beat
SINOATRIAL NODE: sets the rate and timing at which cardiac muscle cells contract
ELECTROCARDIOGRAM: impulses that travel during cardiac cycle cam be recorded
ATRIOVENTRICULAR NODE: impulses from the SA mode travel
42.3 Patterns of blood pressure and blood vessels
Blood Vessel Structure and Function
A vessel's cavity is called the central lumen
ENDOTHELIUM: the epithelial layer that lines blood vessels
BLOOD FLOW VELOCITY
velocity of blood flow is slowest in the capillary beds
the high resistance and large total cross-sectional area
Blood Pressure: the pressure that blood exerts against the wall of a vessel
Blood flows from areas of higher pressure to areas of lower pressure
changes during the cardiac cycle
Systolic pressure: the pressure in the arteries during ventricular systole, highest pressure in the arteries
Diastolic pressure: the pressure in the arteries during diastole, it is lower than systolic pressure
regulation
VASOCONSTRICTION: the contraction of smooth muscle in arteriole walls, it increases blood pressure
VASODILATION: the relaxation of smooth muscles in the arterioles
gravity
systole: 120 mm Hg
diastole: 70 mm Hg
LYMPHATIC SYSTEM: the lost fluid and the proteins within it are recovered and returned to the blood via lymphatic system
LYMPH: circulates within the lymphatic system