adaptions for transport: ANIMALS (C3) Flashcards
Open circulatory system
use insects to explain
OPEN:
-blood is under LOW pressure as NOT contained within vessels
- HEAMOLYMPHY leaves circulatory system it bathes organs directly
- fluid is pumped from LONG DORSAL (top) TUBULAR heart into spaces within body cavity (HEAMOCEOL)
- o2 reaches GE surface via TRACHEAL system , NO respiratory pigment needed to carry o2
- o2 is transported DIRECTLY to tissues
Closed circulatory system
CLOSED:
-blood is under HIGH pressure and CONTAINED within vessels e.g arteries, veins, capillaries
- NEVER directly contact organ
- o2 DIFFUSES into blood and carried bound to HAEMOGLOBIN (respiratory pigment)
- o2 is transported from LUNGS to HEART then towards CAPILLARIES in body TISSUES
Open CS example
insects
Closed CS example and explain the less common one
- mammals
- fish
-earthworms (has DORSAL and VENTRAL vessels running length of body, connected by 5 pairs of PSEUDOHEARTS)
Two types of closed CS with examples
SINGLE circulatory system e.g fish
(passes once)
DOUBLE circulatory system e.g mammals
(passes twice)
Two circuits in double circulation
PULMONARY (lungs) circulation:
blood vessels involved in transporting blood from heart to lungs
SYSTEMIC (body) circulation:
blood vessels involved in transporting blood from heart to rest of body/tissues (excluding lungs)
Advantages of double circulation (4)
- maintains a high pressure in the systemic (body) circulation
- ensuring o2 is delivered to respiring tissues more efficiently - allows for lower pressure in pulmonary (lung) circulation
- prevents build up of tissue fluid in lungs - rapid circulation in the systemic circuit
- efficiently move blood at a larger distance due to faster circulation - oxygenated and deoxygenated blood is kept separate
- maintains a steep concentration gradient for o2 and co2 at tissues and lungs
What transport system is used in mammals?
closed, double
3 types of blood vessels and movements
ARTERIES - transport blood AWAY from heart
VEINS - transport blood TO heart
CAPILLARIES - smallest vessels that allow EXCHANGE of substances with body cells
Layers of the blood vessels
- arteries and veins name 5
- capillaries name 1
arteries and veins: (have the same layers yet proportions differ) -tunica externa -tunica media -tunica intima -endothelium (one cell thick) -lumen
capillaries:
-endothelium (one cell thick)
Function of blood vessel layer structures
- endothelium
- elastic fibers and smooth muscle
- collagen fibers
ENDOTHELIUM: inner most layer, one cell thick, provides a smooth lining = reduces friction reducing resistance to blood flow / in capillaries being one cell thick provides short diffusion path
(1)SMOOTH MUSCLE AND (2)ELASTIC FIBERS: middle layer, (1) thick smooth muscle withstands high blood pressure produced by pumping action of heart, can contract and relax directing blood flow (2) stretch and recoil to maintain high blood pressure
COLLAGEN FIBERS: outer layer, resistance to over stretching
Structure of veins
lumen? walls? muscle layer?
WIDE diameter LUMENS - so can deliver large volumes of blood back to heart
THIN WALLS - pressure inside much lower as further distance from heart
THIN MUSCLE LAYER - can be compressed easily, contracting muscles can squeeze veins pushing blood upwards to heart
Structure of arteries
lumen? muscle/elastic layers?
NARROWED lumen -compared to veins
THICK SMOOTH MUSCLE LAYER - withstand high blood pressure
THICK ELASTIC FIBERS - for elastic recoil to maintain high blood pressure
Structure of capillaries
lumen? wall? features?
NARROW LUMEN - restricts blood flow, slowing blood to allow more time for exchange of materials at tissues
THIN WALL - short diffusion pathway (1 endothelium cell thick)
some capillaries are PERMEABLE to water and dissolved substances e.g glucose, amino acids, o2, co2
What and where are pocket valves?
in the VEINS ensuring that blood flows in ONE DIRECTION (towards the heart)
*maintaining UNIDIRECTIONAL flow of blood in the heart and veins
How do valves work?
- blood tries to flow back
- blood fills pocket above valve
- this forces valve shut
= preventing back flow
(veins in/above heart have no valves as gravity draws blood down toward the heart)
Blood pressure in blood vessels
ARTERIES: high pressure
VEINS: low pressure
CAPILLARIES: falls as velocity of blood decreases