Lecture 26. Circulation and Gas Exchange in Animals Flashcards
What did William Harvey do ?
Correctly proposed how blood flows through animals
What type of animals did William Harvey study ?
Studies lower vertebrates not just humans
When is diffusion inefficient ?
Over large distances
What do some simple animals have instead of circulation systems ?
Gastrovascular cavity and diffusion
What are some examples of animals which do not have true circulatory systems ?
- Sponges
- Cnidaria
- Flat worms
What are the functions of a circulatory system ?
- Respiratory gas transport
- Nutrient and waste transport
- Communication via hormones
- Infection fighting
- Wound healing
- Heat transfer
What are the two types of circulatory systems ?
- Open circulatory system
2. Closed circulatory system
What animals may have open circulatory systems ?
- Arthropods
2. Some molluscs eg. clams
What are some animals that have a closed circulatory system ?
- Annelids
- All vertebrates
- Some molluscs eg. cephalopods
What is an important substance in open circulatory system ?
Hemolymph
What is the fluid used in a closed system ?
Blood
What is the function of pumps ?
- Transport fluid around the body
- Muscular contractions
- Generate flow and pressure
- Regulate stroke volume and stroke rate
What are the two types of closed circulation ?
- Single
2. Double
What types of animals have closed, single circulatory systems ?
Fish
What sorts of animals have closed, double circulatory systems ?
Humans, amphibians
What is the disadvantage of a double, closed circulatory system ?
Requires more energy
What is the disadvantage of closed, single circulatory system ?
Blood pressure to tissues is lower
What does plasma have ?
Low oxygen conductance
How do red blood cells respire ?
Anaerobically
What do red blood cells have ?
Respiratory pigments
What do respiratory pigments carry ?
Oxygen
Do red blood cells have mitochondria ?
NO
What are respiratory pigments ?
Iron containing proteins that transport oxygen
What is the main respiratory pigment in vertebrates ?
Haemoglobin
What is the main respiratory pigment in invertebrates ?
Haemocyanin
What do respiratory pigments have ?
High binding oxygen capacity
What are some examples of respiratory organs ?
- Gills
- Lungs
- Skin
What are the three types of ventilation patterns ?
- Non directional
- Tidal ventilation
- Unidirectional ventilation
What is non directional ventilation patterns ?
Skin - fish, amphibians
What is tidal ventilation ?
Enter and leave through same points - humans, reptiles
What is unidirectional ventilation pattern ?
One way flow - birds, fish
What are some problems associated with breathing underwater ?
- 20 times less oxygen in water than in air
- Water is much more viscous making ventilation more expensive
- Rate of diffusion of oxygen through water is much slower than in air
What is gas exchange ?
Oxygen absorbed, carbon dioxide excreted
How do lampreys breath ?
Mouth is closed but expand and contract the branchial basket, allowing water in and out through gill slits
How do sharks breath ?
Water comes into mouth, past gills and then out
What is ram ventilation ?
Where animals swim constantly forward with their mouth open, forcing oxygenated water into mouth over gills
What is the advantage of unidirectional flow of water across the gills ?
Countercurrent exchange
What is countercurrent exchange ?
Blood flows in one direction and water flows in the opposite direction, it gives a much greater chance of diffusion and oxygen exchange
What are gills composed of ?
Multiple arches
What do arches consist of ?
Threadlike structures called filaments
Where are filaments divided ?
In lamellae containing a capillary area
What is the advantage of multiple arches ?
Maximises area of exchange
What does gill structure correlate with ?
Lifestyle
What do animals with high metabolic rates have ?
Larger gill surface area
What is the caudal fin aspect ration ?
Measure of the shape of the fin
What type of animal is a fish ?
Ectothermic
How do some fish use countercurrent exchange ?
To elevate core temperature
What is myoglobin ?
The oxygen storage protein
How can animals dive under water for long periods of time ?
- More red blood cells
- Myoglobin
- Reduce swimming activity
- Reduce heart rate
- Reduce oxygen consumption rate
How does a rheodytes leukop respire ?
Through its cloaca
What does the water vascular system in echinoderms double as ?
Respiration and locomotion
