Untitled Deck Flashcards
What are the three parts of gas exchange?
1.) Ventilation - diffusion: respiratory surface is exposed to the respiratory medium, and diffusion occurs from the respiratory surface to the inside of the body (usually into blood).
2.) Circulation - diffusion: circulatory system distributes gases into the tissues, they enter through diffusion.
3.) Cellular respiration: oxygen is used up and CO2 is produced as waste (distributed by the circulatory system).
What is the circulatory setup in simple organisms?
Simple organisms have a gastrovascular cavity and are acoelomate, allowing gas exchange through diffusion without a circulatory system.
What characterizes pseudocoelomate organisms?
Pseudocoelomates have a big fluid-filled cavity and usually do not need a circulatory system as body movement circulates the fluid.
Example of Aceolomates
Cnidarians and Flatworms
What is the hemal system in eucoelomates?
The hemal system refers to the circulatory system thought to have evolved once in coelomates, using a pressure gradient to circulate fluid.
What defines an open circulatory system?
In an open circulatory system, hemolymph is moved through body movements, and exchange happens directly between cells and hemolymph.
What is the function of arteries?
Arteries carry high pressure blood away from the heart
Examples of Psuedocoelomates
Nematodes and Rotifers
What is a closed circulatory system?
In a closed circulatory system, blood is kept inside vessels that branch into smaller ones, and there is a mechanism for shunting blood to tissues that need it more.
Circulatory set-up (Eucoelomates)
- Circulatory fluid: blood or hemolymph
- Set of tubes: chambers like Lacunae
3.Muscular pump: that contracts, increasing pressure to push blood through tubules to the heart
How does the spider circulatory system function?
The spider circulatory system is open; hemolymph is drawn into the heart through ostia and pumped out through arteries into the hemocoel.
Spider circulation process
Hearts–arteries–tissue–lacunae/hemoceal–book lungs–ostia–heart
What are the three types of blood vessels?
- Arteries
- Veins
- Capillaries
Open Circ process
- Heart contracts
- Pumps blood hemolymph through vessels
- Dumped into Sinuses called Hemoceal
- Exchange between celLs and hemolymph
- Drawn back into system through pores called Ostea
What is the role of veins?
Veins carry low-pressure blood back to the heart
Open Circ features
- No seperate interstitial fluid or blood
- No capillaries
- No shunting
What is the function of capillaries?
Capillaries are tiny vessels where exchange happens; they have thin walls and form networks within tissues.
Example of Open Circ organisms
Arthropods, Molluscs and Spiders
What is shunting in the circulatory system?
Shunting occurs when smooth muscle in arterioles or arteries constricts blood flow to certain areas of the body that aren’t being used.
What is the purpose of lymph vessels?
Lymph vessels carry lymph back to the circulatory system and help convey excess fluid from tissue spaces.
Close Circ features
- Vessels
- Exchange in Capillaries and Interstitial fluids
- Seperate blood and lymph
What are the two purposes of lymph nodes?
1) Help filter lymph.
2) Provide a place to attack viruses and bacteria.
Examples of Closed Circ organisms
Vertebrates, Annelids, Cephalopods (molluscs)
What is the Law of Continuity?
The Law of Continuity states that if a pipe’s diameter changes, a fluid will flow faster through narrower segments than through wider segments.
What happens to blood pressure in capillaries?
When blood enters a capillary network, blood pressure decreases because the overall cross-sectional area of all the capillaries is much larger than that of the artery.
What is double circulation?
Double circulation involves two separate circuits of blood passing through the heart
Spider Circulation alternative
Tracheal system:
Bypass circulatory system and deliver hemolymph directly to the tissues
What are the benefits of double circulation?
Double circulation maintains higher blood pressure, greater flow to tissues, and allows separation of oxygenated and deoxygenated blood.
Oxygen Debt
Organisms with an open circ system are prone to this as they do not move oxygen super efficiently
Chambered hearts
3 Chambered
2 Atria and 1 Ventricle
EG: Amphibians and Reptiles
4 chambered
2 Atria and 2 Ventricles
EG: Mammals and Crocrodilians and Birds
What is the pathway of blood through the heart?
Superior and inferior Vena cava
Right Atrium
Right Ventricles
Pulmonary Artery
Lungs
Pulmonary Veins
Left Ventricle
Body
Aorta
Caotid and Subclavian arteries
Renal and femoral arteries
What are the types of valves in the heart?
Atrioventricular valves:
- Tricuspid (RA-RV)
- Mitral (LA-LV)
2. Semilunar valves:
- Pulmonary artery (RV)
- Aorta (LV) prevent backflow during contraction.
Artery features
- Thick walls to withstand high pressure
- Smooth muscle layer inside Connective tissue
- Endothelium inside Smooth muscle that reduces resistance (faster blood movement)
- Branch out into Arterioles that deliver blood to Capillaries
What is the coronary system?
The coronary system consists of coronary arteries that connect to the aorta and supply oxygenated blood to cardiac muscles.
What are the phases of the heartbeat?
Systole is contraction, and diastole is relaxation. The sequence includes atrial and ventricular diastole, atrial systole, and ventricular systole.
Vein features
- Thinner walls than arteries
- Contain valves to prevent backflow.
- Movement of skeletal muscle for blood flow
- Capillaries that converge into Venules
- Venules converge in Vena Cava
What is cardiac output?
Cardiac output is the amount of blood the heart moves per unit time, influenced by heart rate and stroke volume.
What are the components of blood?
Blood is mostly water and contains nutrients, waste, gases, hormones, plasma proteins, erythrocytes (RBC), leukocytes (WBC), and platelets.
Capillaries features
- One cell layer thick
- Endothelium surrounded by connective tissue and Basal Lamina
- Multiple routes of passage across network
- Form basis for Shunting
BP Trend
Big-Small= faster blood flow and increased BP
Small-Big= slower blood flow and decreased BP
