HOMEOSTASIS AND EXCERTION- part 2 Flashcards
What is the function of Bowman’s capsule and Glomerulus?
A. Filtration of the blood
B. reabsorption of glucose from the blood
C. reabsorption of urea and water and ions from the blood
A.Filtration of the blood
Liquid which collects in the cavity of Bowman’s capsule is
A. Concentrated urine
B. Plasma minus blood proteins and blood cells
C. salt ions and water
B. Plasma minus blood proteins and blood cells
Explain how the nephron is adapted to its function
Adaptations for ultrafiltration
It has a permeable Bowman’s capsule that only allows substances such as water, glucose, urea and salt ions to pass through but prevents the passage of proteins and blood cells.
The renal artery is highly branched forming small capillaries in the glomerulus and this provides a larger surface area for blood to flow in the kidney for filtration.
the capillaries get narrower in the glomerulus and this builds up higher pressure necessary for ultra-filtration.
Adaptations for reabsorption
Kidney tubules are long and coiled and this provides a larger surface area for reabsorption and more time is allowed for reabsorption of the useful substances. Also the first coiled tubule (proximal convoluted tubule) can allow reabsorption of glucose by active reabsorption and glucose is needed for the body respiration.
The Loop of Henle is U -shaped and this the efficient reabsorption of water and salts.
Explain how the glomerulus is adapted to its function
The renal artery is highly branched in the glomerulus forming a knot of a very small capillaries and this provides a larger surface area for blood to flow in the kidney for filtration.
the capillaries become narrower in the glomerulus this builds up higher pressure necessary for ultra-filtration.
The glomerular filtrate is formed during the process of ……………………. it is collected in the ……………………..
It is further processed along the nephron to form………
The glomerular filtrate is formed during the process of ultrafiltration it is collected in the Bowman’s capsule space
It is further processed along the nephron to form Urine
Sort the following steps when there is an Increase of body temperature fromnormal level
- Thermoregulatory centre (hypothamalus in brain)
receives and processes information - Effectors (muscles or glands) bring about changes (decrease)
- Receptors in thermoregularory centre and skin detect increase
1.Receptors in thermoregularory centre and skin detect increase
2.Thermoregulatory centre (hypothamalus in brain)
receives and processes information
3. Effectors (muscles or glands) bring about changes (decrease)
Our body can only stay at a constant temperature if the heat we generate is balanced and equal to the heat we lose
True or False
True
How does the body respond to changes in temperature?
Increase in temperature
Sweating
Hairs lie flat
Vasodilation
Decrease in temperature
Shivering
Hairs stand up - goosebumps
Vasoconstriction
the blood vessels near the surface of the skin widen to allow heat to be lost from the blood (muscles within the vessels relax).
Vasodilation
the blood vessels near the surface of the skin narrow to reduce heat loss (muscles within the vessels contract).
Vasoconstriction
branch off from the arteries
thinner, less muscular walls (compared to arteries)
feed blood into the capillaries
narrower than arteries, but wider than capillaries
Function: regulate blood flow through capillaries
Arterioles
capillaries join together to form venules
larger than capillaries but smaller (i.e. narrower and thinner walls) than veins
Function: collect blood coming from capillaries
Venules
is a blood vessel that directly links an artery and a vein
A shunt vessel
label the following diagram
Shunt vessels are used when the body is trying to control heat loss through capillaries in the skin:
What happens in a cold environment:
- arterioles get narrower (constrict)
- more blood diverted through shunt vessel
- less blood flows through capillaries
- less heat lost from skin capillaries
Shunt vessels are used when the body is trying to control heat loss through capillaries in the skin:
What happens in a hot environment:
- shunt vessel constricts (gets narrower)
- arterioles get wider (dilate)
- more blood flows through capillaries
- more heat lost from skin capillaries
- body cools down
describe what happens in Sweating & Shivering
sweating
- Sweat glands in the skin release more sweat
- The sweat evaporates, removing heat energy from the skin.
Shivering
Muscles contract rapidly - we shiver.
These contractions need energy from respiration,
and some of this is
released as heat.
describe what happens to hair
Hot environment
Hair muscles relax
Hairs on the skin lie flat
Heat can escape
Cold environment
Hairs muscles contract
Hairs on the skin pulled upwards
Erect hairs trap air
Air insulates against heat loss
How does the human body detect and respond to changes in temperature?
(6 marks – 6 minutes!)
How does the body detect and respond to changes in temperature?
- Temperature receptors in skin detect change in external temperature;
- Temperature receptors in hypothalamus detect change in blood temperature;
- Processing centre is hypothalamus (in brain);
- Nerve impulses sent (from hypothalamus) to effectors;
- Sweat glands produce sweat when too hot; (ora)
- Hair erector muscles contract when too cold; (ora)
- Hairs stand up, trapping a layer of air for insulation; (ora)
- Shivering;
- Is when muscles contract generating heat energy by respiration
- Name the processing centre and an effector which responds to a fall in temperature.
- State 2 ways in which our bodies respond to a rise in temperature.
- State what your core temperature is and why it needs to remain constant (hint – think back to our work on enzymes)
- Explain the difference between vasoconstriction and vasodilation.
- Explain how our bodies control temperature and why
- Explain how negative feedback is used to control body temperature.
- Provide the formula for the reaction that provides heat in our bodies (bonus point for the chemical formula!)
Explain the role of ADH in homeostasis
or
Describe the role of ADH in regulating the water content of the blood.
Homeostasis is maintaining a constant internal environment
Keeping the content of water balanced in the body
the way to do this is the ADH
Antidiretic hormone
it is secreted by the pituitary gland in the brain
if water level is decreased in the body
ADH is released more. which increases the premeability of the collecting duct allowing more water to be reabsorbed and less water leaves the body with the urine , meaning more concentrated urine
if the water content is decreased.
less ADH is released, decreasing the mremeability of the colelcting duct allowing less water to be reabsorbed , meaning more water is leaving the body and more dilute urine
answer the following question in the attached image
Explain the role of structure A
Explain the role of structure B
Explain the cooling mechanisms in humans
(hot environment)
Vasodilation of skin capillaries
Heat exchange (both during warming and cooling) occurs at the body’s surface as this is where the blood comes into closest proximity to the environment
One way to increase heat loss is to supply the capillaries in the skin with a greater volume of blood, which then loses heat to the environment
Arterioles (small vessels that connect arteries to capillaries) have muscles in their walls that can relax or contract to allow more or less blood to flow through them
During vasodilation, these muscles relax, causing the arterioles near the skin to dilate and allowing more blood to flow through capillaries
This is why pale-skinned people go red when they are hot
Sweating
Sweat is secreted by sweat glands
This cools the skin by evaporation which uses heat energy from the body to convert liquid water into water vapour
Flattening of hairs
The hair erector muscles in the skin relax, causing hairs to lie flat
This stops them from forming an insulating layer by trapping air and allows air to circulate over skin and heat to leave by radiation
Explain the warming mechanisms in humans
Vasoconstriction of skin capillaries
One way to decrease heat loss is to supply the capillaries in the skin with a smaller volume of blood, minimising the loss of heat to the environment via radiation
During vasoconstriction, the muscles in the arteriole walls contract, causing the arterioles near the skin to constrict and allowing less blood to flow through capillaries
Vasoconstriction is not, strictly speaking, a ‘warming’ mechanism as it does not raise the temperature of the blood but instead reduces heat loss from the blood as it flows through the skin
Shivering
This is a reflex action in response to a decrease in core body temperature
Muscles contract in a rapid and regular manner
The metabolic reactions required to power this shivering generate sufficient heat to warm the blood and raise the core body temperature
Erection of hairs
The hair erector muscles in the skin contract, causing hairs to stand on end
This forms an insulating layer over the skin’s surface by trapping air between the hairs and stops heat from being lost by radiation
animals that maintain a constant body temperature by phyiological means (mammals and birds)
homeotherm
part of the brain that monitors core body temperature
thermoregulatory centre
sking sensory receptors are located in
dermis
epidermis
hypodermis
dermis
label the diagram
Vasodilation
Vasoconstriction
Normal
explain how controling body temperature is a
negative feedback
negative feedback is
- normal internal environment
- change in the internal environemnt
- change is detected by sensors
- correcting action
- internal environment returns to normal
for controlling body temperature
for example in hot environment this is what happens
Core body temperature (37°C)—>normal internal environment
temperature Increase from normal level—>change in the internal environemnt
Receptors in thermoregularory centre and skin detect increase—> change is detected by sensors
Thermoregulatory centre (hypothamalus in brain)receives and processes information .—–>correcting action
Effectors (muscles or glands) bring about changes—–>correcting action
Fall back tonormal level—–>internal environment returns to normal
what happens in cold environment ?
A.more blood diverted through shunt vessel
B.shunt vessel constricts (gets narrower)
A.more blood diverted through shunt vessel
