U2 Circulatory Systems Flashcards
What happens when an organism’s metabolic rate increases to meet an increasing demand for energy?
Its rate of aerobic respiration and oxygen intake increase
This means that an organism with high metabolic rates need efficient transport systems to deliver large supplies of oxygen to respiring cells
Single circulatory system
composed of one atrium and one ventricle
Blood passed through a two-chambered heart once for each complete circuit of the body.
e.g.fish
DIAGRAM
To the gills
⬆️
Ventricle
Atrium
⬆️
From the body
Incomplete double circulatory system
Heart consists of one ventricle and two atria.
Therefore, some oxygenated blood (from the lungs) is mixed with deoxygenated blood (from the body)
e.g.amphibians and reptiles
DIAGRAM
To the lungs⬅️➡️To the body
From the body➡️Right atrium / Left atrium⬅️from the lungs
Ventricle
Ventricle:
-deoxygenated and oxygenated blood mix
-partially oxygenated blood delivered to tissues
Complete double circulatory system
Heart consists of two atria and two ventricles which are separated
No mixing of oxygenated and deoxygenated blood
The oxygenated blood can be pumped out at a higher pressure
e.g. birds and mammals
DIAGRAM
Pulmonary artery Aorta (to body)
Vena cava. Pulmonary vein
Right atrium. Left atrium
Right ventricle. Left ventricle
3 external abiotic factors that can affect organisms
temperature
ph
salinity
What are conformers?
Their internal environment is dependent upon the external environment.
For example a conformed temperature will also decrease
Advantages and disadvantages of conformers
+ They do not require energy to keep their inner state relatively stable (low metabolic costs)
- They may have a narrower range of ecological niches unless they can tolerate (adapt) or resist variation in their external environments
Why do most conformers have behavioural responses?
To allow them to control their internal environment even slightly
r.g. lizards bask in the sun to raise their body temperature
What are regulators?
They use metabolism to maintain a steady internal environment despite changes in the external environment
Advantage and disadvantage of regulators
+ requires high energy expenditure to maintain homeostatus
- offers a wider range of ecological niches
Homeostasis
Our internal environment must be maintained for us to survive
This is possible due to negative feedback control
state of steady internal environment being maintained
What is negative feedback control?
The process by which a change in factor (eg body temp) triggers a mechanism which results in that factor returning to its normal level (norm or set point)
receptor detects change in factor and sends electrical impulses/messages to the effector which uses a corrective mechanism to return the factor back to the norm
What can thermoregulators do?
maintain their body temperature
What is essential for thermoregulators?
ENERGY for heat is ESSENTIAL for them so they have a HIGHER METABOLIC RAGE
Why is it important for endotherms to regulate their body temperature to around 35-40 degrees?
this is the optimum temperature for most enzymes (which control most reactions in the cells)
Regulating temp also ensures HIGH DIFFUSION RATES to meet the metabolic needs of tissues (If they can’t then metabolic pathways will not function at their best)
(endotherm=an animal that is dependent on or capable of the internal generation of heat)
What is the part of the brain that is responsible for the monitoring of body temperature?
the hypothalamus
How does the hypothalamus work?
It receives nerve impulses (messages) from thermo-receptors in the skin which detect changes in blood temperature
It can then respond by sending nerve impulses to the necessary effectors which return the temperature of the body to its normal level (via negative feedback)
How does skin play an important role in regulating body temperature?
Info is communicated by electrical impulses through nerves to the effectors (eg skin) which bring about corrective responses to return temp to normal
What does the body do when it is overheating?
Vasodilation-ARTERIOLES in the skin surface DILATE which causes an INCREASE in BLOOD FLOW to the surface close to the skin and heat is lost from the blood via RADIATION
Sweating increases-heat from the skin causes water/sweat to EVAPORATE which cools the skin
Metabolic rate decreases-reduces heat being produced in body
What does the body do when it is overcooling?
Vasoconstriction-ARTERIOLES bear skin surface constrict which DECREASES BLOOD FLOW to the surface close to the skin is little heat is lost via radiation
Erector muscles contract-raises the hairs on the skin surface and a layer of warm air is trapped on the surface of skin and acts as an insulator (goosebumps
Metabolic rate increases-heat is generated during metabolic reactions
shivering-involuntary twitching of muscles to generate heat
Why may some animals go through a period of dormancy?
To survive adverse conditions (adapted)
What is their a decrease in during dormancy?
-metabolic rate (to save energy)
-heart rate
-breathing rate
-body temperature
When does predictive dormancy occur?
before the onset of adverse conditions (eg day length shortens)
When does consequential dormancy occur?
after the onset of adverse conditions
3 types of dormancy
hibernation
aestivation
daily torpor
Hibernation
usually mammals
allows them to survive through winter/low temps
eg bear
Aestivation
Allows them to survive through periods of drought/high temperatures
eg crocodile
Daily torpor
within a 24 hour period
seen in animals with a high metabolic rate
eg birds and small mammals
Heart rate, body temp and breathing decrease
What is migration?
The seasonal movement of members of the same species from one region to another
This behaviour AVOIDS metabolic adversity
Energy is used to relocate to a more suitable environment
Migration-innate behaviour
Inherited so is inflexible
Part of the genetics of the organism
eg humpback whale
Migration-learned behaviour
begins after birth and is gained from experiences
flexible and based on trial and error
eg wildabeest
Migration can be innate and learned. What plays a primary role and secondary role?
Innate-primary role
eg birds migrating due to an external stimulus such as day length
learned-secondary role
Why do scientists track animals?
To find out:
-when animals migrate
-where they go over winter
-if and when they return to original summer territory
-how long they live for
Techniques for tracking animal migration
leg rings
-bands placed on leg of organisms
-specific id number which can be logged each time the individual is captured
-OR different combos of colour bands (easily identifiable without recapture
eg birds
satellite tracking
-tracker attached to animal
-gps tech used to track
-no recapturing needed
-data is precise
-tech is very expensive
-eg whale
