Endocrine And Integumentary System Flashcards
Why is the pressure in the glomerulus high?
As the affront arteriolar is wider than the efferent arteriol.
What does this high pressure (in the glomerolus) cause?
a bottleneck in the capillaries. Here the pressure pushes water and smaller molecules from the blood in the capillaries in the glomerulus all the way to Bowman’s capsule by ultrafiltration.
Where is selective re absorption carried out?
Proximal convoluted tubule
how is glucose reabsorbed from the filtrate in PCT?
-glucose enters the PCT (proximal convoluted tubule) by facilitated diffusion
-Glucose pairs the PCT cell at the other end and diffuses into teh blood
-Active transport is also involved in the re absorption of glucose fro the PCT cells into the blood.
what happens to the water conc as glucose is reabsorbed?
Decreases the water conc creating a water concentration gradient down which water enters PCT cells by osmosis from the filtrate.
Where does the filtrate enter after the proximal convoluted tubule?
Enters the loop of Henley which drops down into the medulla and rises back up into the cortex.
What happens in the ascending limb?
At the top they pump out sodium ions by active transport as the walls are impermeable so cannot leave. Creating a low water conc in the tissue fluid of the medulla.
What happens in the descending limb?
The cells are highly permeable to water but impermeable to sodium ions. So water moves out and enters the tissue fluid of the medulla by osmosis. This makes the filtrate in the descending limb more concentrated, reducing it’s water conc.
Label the kidney
.
Label the pancreas
.
What is the pancreas used for?
Control of blood glucose levels.
What does the islets of langerhans contain?
Alpha cells and beta cells
Label the nephron
.
What do receptors in the islets of langerhnas monitor?
The glucose concentration of the blood.
What happens when blood glucose levels climb?
-Detected by receptors in the IL
-Beta cells are secreted. targets the liver and muscle cells.
-These cells take up more glucose than normal and store the excess as glycogen
What is glycogen and what are its main features?
Glycogen is a branched polymer of alpha glucose. it is compactly so stores a large amount of glucose on a small space. It is highly branched so it has lots of ‘ends’ for enzymes to attach to and hydrolyse it quickly if needed.
What happens when low glucose levels are detected?
Receptors detect this and the alpha cells will secrete glucagon into the bloodstream. Glucagon mainly targets the liver and it causes the breakdown of glucagon into glucose which is released into the blood raising by levels.
What is glucose?
A monosaccharide that makes up carbohydrates and disaccharides. Is a hexose sugar and a main respiratory substrate.
What is glycogen?
Polysaccharide, long polymer chain of glucose. Compact so stores large amounts of glucose. Highly branched
What is glycogenisis?
When cells take up more glucose than normal and store the excess as glycogen. Condensing the glucose into glycogen.
What is glycogenlysis?
This is caused when the hydrolysis of glucagon into glucose is released into the blood raising blood glucose levels.
Where is the water in the tissue fluid of the medulla reabsorbed?
Vasa recta
Why is the loop of Henley known as the countercurrent multiplier?
As the fluid flows in the opposite directions in the two sides of the loop.
Where does the filtrate go after the loop of henle?
Distal convoluted tubule.
What is glucagon?
Hormone released by alpha cells in response to low BG cells. Stimulates liver cells to carry out glycogenlisis.
What is insulin?
A hormone released by beta cells in response to high blood glucose levels. Stimulates liver and muscle cells to carry out glycogenisis.
What is osmoregulation?
The homeostatic mechanism that controls the water concentration of the blood.
What is ADH?
A peptide hormone synthesised in the hypothalamus and stored in the posterior pituitary to be released into the bloodstream
How do the kidney’s receive blood?
From the aorta via the renal arteries
How is blood returned from the capillaries?
Renal veins return blood to the vena cava
What is the renal capsule?
Bowman’s capsule together with it’s glomerolus
What blood vessel brings blood in?
Afferent arteriole
Which blood vessels brings blood out?
Efferent arteriole
Label the skin
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what does subcutaneous fat in the deeper layers of the skin act as?
Energy storage area
What are the proteins in the skin responsible vitamin D for?
harnessing U.V radiation and using it to convert cholesterol into
How does shivering help reduce heat loss?
The involuntary contracting increases the rate of respiration in these muscles, releasing excess energy as heat.
What does the hair do to reduce heat loss?
Erector muscles will contract, causing hairs to stand up on end. This traps a layer of air next to the skin, acting as an insulator and reducing heat loss.
How does the adipose tissue help reduce heat loss?
The fat cells below the skin surface act as an insulator, reducing heat loss through the surface of the skin.
What is vasoconstriction?
Muscle tissues in the walls of the arteriole contracts, narrowing and reducing the volume of blood flowing through them.
what do the capillaries next to the skin do to help reduce heat loss?
Arteriole leading to the capillaries close to the surface of the skin will vasoconstrict, causing a decrease in volume of blood flowing close national the surface of the skin. this will reduce heat loss by radiation.
What is skin?
An organ that surrounds the body and it’s the first line of defence in preventing foreign bodies from entering.
What is in the skin that makes the cells harder and prevent mechanical damage?
Keratin
What does melanin do?
Darkens the skin and protects tissue underneath from being damages by solar radiation
What is thermoregulation?
Control of body temperature
What is the hypothalamus responsible for?
Things such as: hunger, sleep and temperature regulation
What is the area of the hypothalamus that is dedicated to the control of body temp?
Thermoregulatory centre
How does sweating help with heat loss?
When we sweat this evaporates from the surface of the skin, with this excess heat energy when it evaporates it carries the energy causing the cooling of the skin.
What do hairs do to cause heat loss?
The erector muscles of the hair relaxers, causing the hairs to lay flat on the surface of the skin. This helps heat loss as the hairs don’t trap an insulating layer of air next to the skin.
What is meany by vasodilation?
The muscle in the walls of the arterioles relax, making the lumen wider and allowing an increased volume of blood to flow through them.
What happens to the capillaries next to the skin to help with heat loss?
Arterioles leading to capillaries close t the surface of the skin vasodilate , causing an increase V of blood flow close to the surface of the skin. this increases heat loss from the blood by radiation.
What are the two main functions of the kidneys?
EXCRETION i.e. filtration of blood to remove urea
OSMOREGULATION i.e. the kidney maintain the blood at a constant water conc despite wide variation in salt and water intake.
What happens if there is an increase in water conc of the blood?
-detected by osmosreceptors in hypothalamus.
-less ADH released from the posterior pituitary
-Collecting duct walls less permeable
-less water reabsorbed into blood. More urine produced.
-Decrease in water conc of the blood.
What happens if there is a decrease in water conc of the blood?
-detected by osmoreceptors in hypothalamus
-More ADH released from the posterior pituitary gland
-collecting duct walls more permeable
-more water reabsorbed less urine produced
-Increase in H2O conc of blood.
What are 3 symptoms you would expect in a person with a lack of ADH?
-more urine produced
-more sweat
-dehydration and thirst
-electrolyte/mineral in balance
Which arteriole glomerolus is wider?
Afferent
What is the Bowman’s capsule lined with?
Podocytes
What do podocytes (that line Bowman’s capsule) contain?
Finger-like gaps as they fit close together wrapping around the capillaries making up the glomerulus, this forms tiny filtration slits.
What is the capillary separated from the podocyte by?
A basement membrane made of a mesh of fibres
why do you need the capillary to be separated by the podycyte?
As the capillary has pores in it so this membrane acts as a continuous barrier to filter. Meaning RBC, platelets and plasma proteins are too large to pass through.
