3. Circulation II Flashcards
(13 cards)
What type of circulatory system does a hagfish have?
Partially open circulatory system
Hagfish have several muscularized blood vessels that act like hearts and a unique caudal heart.
How does the heart of a hagfish differ from vertebrate hearts?
It has 2 chambers separated by a cartilaginous rod
Muscles contract to bend the rod, changing the volume of each chamber.
Describe the circulatory system of teleost fish.
Simple closed system
The heart pumps deoxygenated blood through gills, and reoxygenated blood circulates to the body.
What is the function of gills in fish?
Gas exchange
Gills facilitate oxygen uptake through unidirectional flow of water over them.
What is counter current exchange in gills?
Opposing flow of water and blood maximizes oxygen uptake
Ensures a strong diffusion gradient for oxygen.
What are the structural components of gills?
- Gill arch
- Gill filaments
- Secondary lamellae
These structures provide support and increase the surface area for gas exchange.
What are secondary lamellae?
Thin, plate-like structures on gill filaments where gas exchange occurs
They are highly vascularized to facilitate oxygen diffusion.
What unique respiratory feature does a lungfish have?
Both gills and lungs (modified swim bladder)
Lungfish can use lungs to take in oxygen when water ppO2 is low.
How is the heart of a lungfish structured?
Has two atria
This separates blood returning from lungs and the rest of the body.
What two circulatory circuits do land vertebrates have?
Pulmonary and Systemic
This structure supports efficient oxygen transport and distribution.
How do amphibians respire in different life stages?
Tadpoles use gills; adults use lungs and diffusion through skin
During winter, skin respiration is more prominent due to lower metabolic rates.
What is the heart structure of adult amphibians?
Partially divided heart with 2 atria and one mixed ventricle
The incomplete divider allows some mixing of oxygenated and deoxygenated blood.
What is unique about the respiratory system of turtles?
Only lung respiration with a partially divided heart
The heart has folds and grooves to act as channels and reduce mixing of blood.
