Ch 42 Respiration and Circulation Flashcards
Blood
The fluid medium for transport on the scale of the whole multicellular animal
Blood functions in the transport of
1) Cell and products of the immune system
2) Gases
3) Heat
4) Hormones
5) Nutrients
6) Wastes
7) Water
Erythrocyte
Red blood cell
Leukocyte
White blood cell
Erythrocytes of birds and mammals originate where?
In the bone marrow
What is true of the erythrocytes of birds and mammals that is not true of all other eurythrocytes?
They lose their nuclei and most organelles
All other vertebrate eurythrocytes retain their nuclei
Unique characteristic of mammal eurythrocytes
Biconcave shape
Increases surface area
Platelets
Cytoplasmic fragments that are produced by large cells residing in bone marrow
What role do platelets play in clotting?
They adhere to break in blood vessels and initiate a cascade of reaction leading to blood clotting
Open circulatory system
1) Blood is merely hemolymph
2) Low pressure
3) Often not involved in O2 transport
Hemolymph
Extracellular fluid
Closed circulatory system
1) Blood is only 5-10% of body volume
2) High pressure
3) Extensive branching into tiny capillaries
Homocoel
Body cavity where the hear and all organs of insects and other arthropods lie
How does hemolymph enter the heart of insects and other arthropods?
Through valved openings and is pumped towards the head
Annelids have what kind of circulatory system?
The simplest full, closed circulatory system
Circulatory system of fish
Single circuit
Two-chamber heart pumps blood first through a gill capillary system and then through a systemic capillary system
Circulatory system of tetrapods
Two-circuit
Separate pulmonary and systemic circuits for higher blood pressure and more efficient O2 delivery
How many chambers does the heart of amphibians and nonavian reptiles have?
Three
Circulatory system of birds and mammals
Two-circuit
Separate atria to collect blood and separate ventricles to pump blood to the pulmonary and systemic circuits
How many chambers does the heart of birds and mammals have?
Four
What keeps blood flowing in one direction?
Heart valves
Artery tissue vs Vein tissue
Arteries have thicker layer of elastic connective tissue and smooth muscles than do veins
Artery diameter vs Vein diameter
Veins have a greater internal diameter than arteries
Capillary walls
Comprised of a single layer of epithelial cells
Arteriosclerosis
A thickening and loss of elasticity in the arteries
What causes a heart attack?
Clots
What causes clots?
Arteriosclerosis and accumulation of fatty cholesterol plaques
Capillary density in muscle
Can be denser than one million per square inch in muscle
What regulates blood flow to capillaries?
Sphincters at their point of departure from the arterioles
What is the link between the arterial and venous system?
Capillary beds
Capillary beds are the site of what?
Ion, nutrient, and water exchange
What happens as blood flow slows?
Diffusion increases and fluid and small molecules enter the extracellular spaces
Higher inital blood pressure in the capillaries leads to what?
It forces fluid into the interstitial space between cells
What role do large molecules play in the capillaries?
Large molecule cannot escape the capillaries and, therefore, increase in concentration making the blood hyperosmotic
External respiration
The exchange of O2 and CO2 between an animal and its environment
How much of blood is water?
Less than 1%
How much of blood is oxygen?
21%
What facilitates external respiration in insects, the millipedes, and some spiders?
An intricate system of tracheae and tracheoles
Does blood play a role in oxygen transportation in insects, millipedes, and spiders?
No
In mammals, what moves air in and out of the lungs?
Muscles attached to the ribs
In mammals, gas exchange occurs where?
Across the surface of the alveoli
Birds have what kind of respiratory system?
A through-flow respiration system pumped by posterior and anterior air sacs
Hemoglobin
An oxygen carrying protein molecule in all vertebrates and many invertebrates
How much of the oxygen needed by humans is dissolved in blood plasma?
~1%
How much of the oxygen needed by humans is dissolved hemoglobin?
20%
When does hemoglobin bind O2?
When its in a high oxygen environment
When does hemoglobin release O2?
When it is in a low oxygen environment?
Why is oxygen delivered most to the most active sites?
Because both CO2 and lactic acid (from anaerobic respiration) lower blood pH
Myoglobin
A protein that binds oxygen in muscles
Mammalian dive reflex
A respiratory and circulatory reflex to conserve O2 is initiated by cold water contacting the face of mammals
Mammalian dive reflex causes:
1) Heart rate to slow
2) Peripheral blood vessels to constrict
Due to the mammalian dive reflex, what happens in very deep dives?
Plasma and interstitial fluid move into the chest cavity
