circulatory systems

Samantha bruce
Flashcards by , created 2 months ago

lecture 6 and 7

Samantha bruce
Created by Samantha bruce 2 months ago
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Question Answer
name the major functions of the circulatory system gas transport waste removal nutrient transport transport and circulation of signalling molecules such as hormones and allowing for homeostasis transport of immune cells distribution of heat evolved to overcome the limitations of diffusion
describe a closed circulator system -fluid is confined to the blood vessels - walls have a specialised lining - all substances have to diffuse across the wall - fluid is separated from the tissues
describe an open circulatory system -fluid flows through open spaces these are called sinuses -the fluid is in contact with tissues
name 2 types of blood cells leukocytes and red blood cells
what circulatory system does lymph accompany open lymphatic system return filtered fluid back to the circulatory system maintaining bp occurs when the ultra filtrate of blood is removed from the blood at high pressures
what is haemolymph involved with the immune system but is less specialised found in open systems where there is no distinction between the blood, lymph and interstitial fluid composition similar to blood but less specialised
describe the external pump - propels circulatory fluid forward - not part of the blood vessel - surround the skeletal muscle vessels -contraction is pattered with the one way pumping system of the vessel moving blood forward -this allows and uses body movements to ensure the movement of blood
give an example of where the skeletal muscles are essential? animal used by many arthropods - grasshoppers heart only active when the organism is inactive -uses only the external pumps when moving horses -skeltal pumps in the legs ensures blood reaches these regions
peristaltic pumps -peristaltic waves of contraction that moves the blood through the lengths of vessels -inside vessels --> contained within walls contractile vessels- whole vessel has the ability to contract peristaltic hearts- only a region is capable of contraction
discuss properties of chambered hearts simplest case = single chambered with unidirectional blood movement more complex hearts in closed systems as higher pressure is required to move the blood around the system accessory Hearts that work with the 'main' heart
how is cardiac contraction controlled nervous synchronisation
what is the major function of the atria reservoir for fluid
major ventricle function pumping structure more muscular
name the basic vessels of the circulatory system heart arteries arterioles capillaries venules veins
what is the function of the capillaries diffusion -thin walled small diameter dense networks
what is the function of the veins and arteries blood transport these have thick walls
name the 4 layers of the veins and elastic arteries tunica externa tunica media tunica intima endothelium
name the 2 layers of the venule tunica externa endothelium
name the 2 layers found in the arteriole tunica media endothelium
name the cell type that makes up the capillaries endothelium
why do the veins and arteries differ in structure - different properties are required for their functions
describe tunica externa thicker in arteries than in veins this contains collagen
describe the tunica media much larger in arteries than veins contains smooth muscles that allow for the contraction of the vessels that change the diameter
describe the tunica media specialised endothelial lining that is on the inside of the vessels
describe arteries very thick walled carry blood from heart at high pressures need thick muscular wall to withstand pressure elastic- contain large amounts of lalstin proteins able to expand movement from large arteries to smaller arterioles requires expansion
describe veins carry blood to the heart at lower pressure slower speed risk that the blood will back up in the system e.g. 60% of the human blood is contained with the veins at all times large lumen that takes up blood volume generally thin walled
describe the evolutionary origins of both open and closed systems open= thought to be older - molluscs, annelids and chordates closed= evolved independently in 3 different groups -annelids, molluscs, vertebrates
describe the arthropod circulatory system open one heart (at least) and some vessels heart always on the dorsal side of the body
what is systole Systole is the last stage of a heart beat. During systole, the heart's two ventricles contract (squeeze). (The ventricles are the largest parts of the heart, which pump blood to the body and lungs.)
what is diastole Diastole is the part of the cardiac cycle during which the heart refills with blood after the emptying done during systole
describe the contraction of arthropod hearts -when the heart is contracting the ostium (holes in the heart) are closed and pressure builds up blood pushed from the heart through into the veins during diastole heart volume increases this is aided by the elastic recoil of the suspensory ligaments volume increase is coupled with a pressure drop ostium open, and haemolymph enter the heart due to the Lower pressure
describe the circulatory system of crustaceans -complexity varies related to size and activity of the species one example would be the fairy shrimp with a very simple system crayfish- peristaltic heart with Brach vessels that resemble capillaries resin casts of blue shrimp show much more complexity- partially closed system capillary bed indistinguishable
describe the insect circulatory system -simple many species have accessory hearts these are common near limbs and long appendages where the main heart would have difficulty main heart typically only pumping where the insect is inactive
how can it be determined that accessary hearts are evolutionary innovations they are not homologous with any other structures -->components recruited from different organ systems and used to form heart
describe the circulatory system of the mollusc typically 2 chambered hearts open system with some vessels more active cephalopods have closed systems -commonly have 2 brachial hearts the brachial hearts are just before the gill and provide the force to move the blood through the gills
what surrounds the atrium and ventricle in mollusc heart pericardium - creates the force to generate the pressure moving the haemolymph out of the heart
describe the circulatory system in annelids simplistic and peristaltic hearts circulatory system in the annelids differs between closed and open depending on the species
name an annelid that has an open circ. system polychaetes
name an annelid that has an closed circ. system oligochaetes - have 5 hearts that connect the dorsal and ventral vessels this is a longitudinal system - running the entire length of the animal
fish heart 4 chambers - different to humans though atrium ventricle sinus venosus bulbous arteriosus single circuit with the blood passing through the heart only once
what is the function of the bulbous arteriosus smooths out pressure fluctuations when the heart contracts
what is the function of the gas bladder contains oxygen that is introduced before the heart possible heart oxygenator as the heart only receives deoxy blood hops the heart perform efficiently
what issue could arise with the use of the gas bladder before the heart pp of oxygen in the blood before the heart decreases not as steep between the blood and the external media gas exchange would therefore not be as efficient in the gills the gas bladder therefore is most likely an adaptation to deal with waters that have very low oxygen and the gills become non functional
what is the difference between fish typical fish hearts and the hearts of the African lungfish intermediate between single and double circ. this improves the efficiency use of both gill and lungs water and air breathing this allows from blood to be shunted to the lungs or the gills depending on where it is easiest to extract oxygen at the time
describe amphibian heart 3 chambered heart 2 atria 1 ventricle partially separated heart ventricle undivided
explain why the design of the amphibian heart is not a poor design separated system would be a poor design -->amphibians use cutaneous respiration on which larvae rely on heavily blood returning from BOTH the lungs and the skin is oxygenated capable of sending oxygenated and deoxygenated blood to different parts of the system as it is required remember PP would be less steep if oxygenated blood was sent to skin and there fore would prevent gas exchange
describe reptilian hearts non crocs=typically considered to have 5 chambered hearts - however this is not true this is not true but the ventricle is subdivided into 3 double circulation that isn't fully separate flexible
name the 3 compartments of the ventricle in the reptilian heart (non croc) Cavum pulmonale cavum venosim cavem arteriosum
how is the mixing of oxygenated blooded deoxy blood in reptiles prevented muscular ridge careful contractile timing direction of flow
what is the advantage of the reptilian heart design ectothermic have lower oxygen requirement allows for shunting of the body and lung circuit - both are not always functional this is advantageous in reptiles that spend period of time in water or have periods of apnea pumping to the lungs would not be energy efficient
describe the hearts of birds and mammals double circulation that is fully separate lung and body circuits 4 chambered hearts 2 atria and 2 ventricle
how can it be determined that mammals and bird both suit their circ. system being fully separated - developed independently in both words and mammals -both are endotherms and have high energy requirements
describe the functions of the circ. system in mammals and birds constant high pressure delivery of oxygen to the body tissues - separated circuit means that it is possible to have different pressure in the circuits -high pressure body circuit to provide oxygen to tissues -much lower in the lungs where the capillaries are delicate
what effect would pumping blood to the lungs at the same pressure that is moves into the body system ultrafiltration of the blood into the air filled spaces resulting in edema and reduced ability to exchange oxygen
what effect does the separated system have on the muscle density in the respective ventricles left- pumping to the body is more muscular that the right where the blood is moving to the lungs
mammals and birds have one aorta, this is different in reptiles; why? reptiles have 2 systemic arches this means that the blood in the bird and mammal system travelling through at higher pressure as it is concentrated to one rather that bracing this is necessary as the lungs cannot be shunted as the heart is fully divided and always required to move through the lungs where it would be dangerous to move blood at these higher pressures
describe the hearts of crocodiles 4 chambered hearts similar to birds and mammals with 2 systemic loops these leave the heart from both of the ventricles -one on the left and one on the right there is a connection between these - foramen of panizza allows for a flexible system, bypassing the lungs if needed but cannot bypass tissues
explain the hypothesis as to the evolutionary development of the crocodiles heart croc= echo thermic leads to the belief that crocodile ancestors may have been active terrestrial endotherms and may have converted to ectothermic then they became aquatic bush hunters
why are ectotherm circulatory systems generally described as flexible able to shunt and control blood flow
why are ectothermic systems typically more strict constraints of high metabolic demands