Excretory System Flashcards
What is excretion
The removal of waste products from the body
What is secretion
The release of useful substances by the body
What happens when there’s an accumulation of excess water
Homeostasis is disrupted which leads to complications
Define homeostasis
Maintaining a constant internal environment through self regulating mechanisms
What is deamination
The removal of amino acids
Name types of nitrogenous waste
Urea, uric acid and creatinine
How is urea formed
Amino acids are broken down into ammonia and deaminated into urea
Name types like of non-nitrogenous waste
Toxins, drugs, Carbon Dioxide, excess water and ions
What happens when too much alcohol is consumed
It causes cirrhosis if the liver
What are other excretory products formed in the liver
Bile pigments and cholesterol
How are bile pigments formed
From the breakdown of red blood cells( erythrocytes)
How is Cholesterol formed
From the breakdown of bile salts
What are the types of cholesterol
High Density Lipids- Healthy
Low density Lipids- Lethal
Metabolism
Body converts food into complex forms of chemical energy and then into usable energy
Types of metabolism
Anabolism and catabolism
Anabolism
Constructive metabolism
Catabolism
Destructive metabolism
List excretory organs
Kidneys, lungs, Skin and Gut Colon
What is the function of kidneys
To filter nitrogenous waste out of blood and regulate water and salt balance
The function of lungs
To release Carbon Dioxide, some heat and water through Cellular respiration
The function Of the Skin
To release swear from the swear glands so that the body can permeregulate
How does swear help us permeregulate
Heat is lot and the body is cooled
Function of the Gut Colon
To excrete bile pigments and cholesterol formed in the liver in the faeces
What else is excreted in the faeces
Mucus and bacteria
What is defaecation/ egestion
The removal if undigested and unabsorbed food material (faeces)
What is diffusion
Moving from a high concentration to a low concentration
What are important irons excreted which influence pH
Hydrogen and potassium
What is NSAD
Non Steroidal Anti-inflammatory Drugs
Organs which are not excretory organs
The Liver and the bladder
What is the function of the Bladder
To store urine
What is micturition
To pee
What is osmolarity
About how much stuff is dissolved
What does Hypertonic mean
That there’s of salt thus meaning low osmolarity
What does Hypotonic mean
That there’s little salt thus meaning high osmolarity because it has alot of water to give away
What do osmoreceptors do
They monitor the osmolarity of the blood
What is to stimulate
To make something more, start it or make it faster
What is to inhibitate
To make something less, stop or slow it down
Where is the urinary system found
In the abdominal cavity
Dorsal
Towards the back
Ventral
Towards the belly
What is the function of the inferior vena cava
It’s a branch of the aorta
It carries purified, deoxygenated blood back to the heart
What is the Renal Artery and what does it do
Carries unfiltered, oxygenated blood and nitrogenous waste to the kidney
What does the renal vein do
Carries deoxygenated and purified blood from the kidney to the inferior vena cava
What does the Ureter do
It carries urine from the pelvis to the bladder
What does the urethra do
It carries out urine from the bladder
Function of the sphincter muscle
It’s a voluntary muscle that controls the flow of urine
Function of the adrenal gland
To secrete aldosterone to regulate the salt concentration in the body
Why is it less likely for males to get kidney infections
Because their urethra runs through the penis, so it’s long
Why is it more likely for female to get bladder infection
Because the urethra is shorter and the opening us closer to the anus
Function of the renal capsule
Tough n fibrous, preventing infections
What does adipose tissue do
Hold the kidney in place and cushions it
Renal fascia (outer layer of fibrous connective tissue)
Anchors the kidney to the surrounding structures
Renal helium
Where everything goes in and out
What is the cortex
The reddish area made up of renal corpuscles which has more blood
What is the medulla
Is the brownish area made up of 8-12 pyramids
What are pyramids
Made up of about 12 collecting ducts
Function of the Calyx
It collects urine form the collecting ducts
What is the Papilla
The border between the calyx and the pyramid
What is the Renal Pelvis
It’s the enlarged upper end of the ureter
Convex
()
Concave
)(
How is the blood entering the kidney
-through the artery
-it’s unfiltered
-has high urea content
-rich in nitrogenous waste
How is blood leaving the kidney
-through the vein
-Filtered
-Low urea content
-deoxygenated
-purified
What is a nephrologist
A kidney specialist
Where’s is the Nephron found
In the cortex and medulla areas
What is the function of the Nephron
Removes waster matter from the blood
Difference between afferent and efferent arterioles
Afferent= has wider diameter & goes towards Nephron
Efferent= goes away from Nephron
What is the glomorulus
The cluster of capillaries
How do kidneys maintain homeostasis
By removing unwanted substances from the blood
The major process of the kidney
Glomerular filtration
Tubular re absorption
Tubular excretion
Where does Glomerular filtration take place
In renal corpuscles
What is glomerular filtration known as and why
Ultrafiltration because it happens under pressure
Process of Glomerular filtration
- Blood enters through the wider afferent arteriole
- More blood enters than leaves
- Pressure builds up forcing filterable contents of blood into the cavity of bowman’s capsule
How is the glomerular membrane adapted for filtration
- Endothelial cells- are porous allowing plasma (+ proteins) through
- Podocyte layer of bowman’s capsule- has cells with filtration slits
What makes up the glomerular filtrate(plasma)
Useful substances such as water, glucose, amino acids and hormones
Waste substances such as urea, uric acid and creatinine
What is Glomerular filtration
A passive, non-selective process in which fluids and solutes are forced through the glomerular membrane by hydrostatic pressure
What is hydrostatic
Water causing pressure
The process of Tubular Reabsorption
As the filtrate moves along the renal tube, the useful substances are re absorbed back into the blood in the capillaries
Where does Tubular re absorption take place
Mainly in the proximal tubule
How is the proximal tubule adapted for re absorption
Long and coiled- enabling maximum re absorption
It’s surrounded by a capillary network so substance can be transported by bloodstream
Its wall has cuboidal epithelial cells with mitochondria for active transport
Concentration gradient
The gradual difference in the concentration of solutes in a solution between two regions
What is ATP
Adenosine Triphosphate Energy
What are the two types of re absorption
Active reabsorption and Passive reabsorption
What happens in Active reabsorption
Organic nutrient like glucose, proteins and water soluble vitamins are completely reabsorbed into the blood
Why would the body reabsorb Vitamin A
For the Eyes
Why would the body reabsorb Vitamin D
For the bones
Why would the body reabsorb Vitamin E
For the Skin and the nervous system
Why would the body reabsorb Vitamin K
For blood pumping
Why would the the body reabsorb Vitamin C
For immunity
What happens in Passive reabsorption
65% of water is passively reabsorbed from the filtrate into blood
Chloride ions follow the path of sodium ions
What is active transport used for
To transport bigger molecules n stuff
Why do we get fat when we eat too much sugar and exercise little
Because glucose never gets excreted from the body
What is PTCN
Peritubular Capillary Network
Why does normal urine not contain glucose or protein
Because they are reabsorbed back into the blood
What is the role of the loop of henle
To actively conserve water and pass it back into the blood so it’s not lost in urine. Allowing less urine to he formed n is dark yellow (concentrated)
What happens when the loop of henle is longer
There’s greater concentration of salt in medulla area so more water is reabsorbed resulting in highly concentrated urine
Where does Tubular excretion take place
In the proximal and distal tubules of nephrons
What happens in Tubular excretion
Hydrogen ions(H+) and potassium ions(K+) move into filtrate
Sodium ions move back into blood
Water follows sodium ions my osmosis
Creatinine & uric acid move into filtrate
Undesirable substances like drugs ste actively excreted
Summary of Glomerular filtration
The fluid part of the blood is filtered from the glomerulus into the cavity of the bowman’s capsule
Summary of Tubular reabsorption
As this fluid flows along the renal tubule, useful substances are reabsorbed back into the bloodstream in the amount required by the body
Summary of tubular excretion
Certain unwanted substances in the blood are actively excreted into the tubules
What is pH
A measure of the hydrogen ion concentration in a solution and as such is a measure of acidity or alkalinity
What happens if there’s more hydrogen ions in a solution
There’s greater acidity if the solution
What is pH 7
Neutral
What is pH lower than 7
Increase in acidity
What is pH higher than 7
Increase in alkalinity
What to hydrogen ions produced by metabolism do
They lower the pH so the body had buffer systems to keep the pH in range
What foes pH range in
Blood- 7.35-45 (slightly alkaline)
Urine- 6 (weakly acidic)
What is a buffer
A chemical substance that prevents too great change in pH
What does a buffer do when pH drops
It binds with hydrogen (H+)
What does a buffer do when pH rises
It released H+
How can excretion of urine play a big role
It can get rid of hydrogen ions, regulate the pH and maintain homeostasis
What is urine
The filtrate that flows from the collecting duct, that contains all the substances that the body does not want
What affects the composition, amount and colour of urine
Diet, exercise and volume of liquids drunk
What is the composition of urine
96% water
1.5% Salts
2% urea
Small quantities of uric acid, creatinine and ammonium ione
How much urine does a full bladder hold
200ml but can hold double
What is urination
A reflex action triggered by the filling of the blafder
What do impulses form the autonomic nervous system do
They stimulate the bladder muscles to contract and the internal sphincter to relax
How does urine move out of the kidneys
Collecting ducts
|
Renal calyx then renal pelvis
|
Two ureters the bladder
|
Expelled through urethra
How do kidney maintain homeostasis
By regulation of the chemical composition of the blood
How can molecules move passively
Through osmosis and diffusion
What is water potential
How the movement of water molecules in a solution exert pressure on a membrane
How does water move in Osmosis
From a high water potential to a lower water potential through a differentially permeable membrane
What does the presence of a high concentration of solutes in a solution of water do
They decrease the number of free water molecules in the solution, lowering water potential and forming a hypertonic solution
What does a lower concentration of solutes do
Doesn’t decrease the number of water molecules, increasing water potential and forming a hypotonic solution
What is an isotonic solution
When the solution on both sides of a membrane have the same free water molecules so no concentration gradient so nothing moves
What is a concentration gradient
When the concentration of something is higher on one area than on the other
What is the water potential of pure water
0
What happens as solutes are added to water
The water potential decreases (—)
What happens when molecules move actively
They combine with a carrier molecule & may move against concentration gradient
What is Osmoregulation
To maintain the correct balance between the water and solute contents of the body fluids
What controls Osmoregulation
The kidneys and the skin
What is osmolarity
The number of soluble particles dissolved in one litre of water
What do we need to keep constant for the cells in the body to function
The amount of water and the concentration of solutes
What does too little water cause
Dehydration of the cells
What does too much water cause
It cause the cells to burst
The greater the concentration of solutes
The greater the osmolarity n the greater the tendency or water to move into this hypertonic solution by osmosis
What do kidneys do when fluid intake is low
They form more concentrated urine through sodium pump which makes the medulla salty so water moves from filtrate to blood
What is Antidiuretic Hormone
Is a hormone secreted by the hypothalamus
What are osmoreceptors and what do they do
Special cells in the hypothalamus that monitor the osmolarity of the blood
Wheat happens when osmolarity increases due to dehydration
The thirst centre is stimulated, causing more water to be drunk
The pituitary gland released ADH
What role does ADH play
Makes tubules to be more permeable to water, allowing extra water to he absorbed into the blood and causing less but more concentrated urine to be secreted
What happens when the osmolarity of the blood and body fluid reduces
The receptors of the hypothalamus are not stimulated and less ADH is secreted, so more urine is excreted
A negative feedback system
a change in a regulated variable triggers a response which reverses the initial change and brings the regulated variable back to the set point.
What does ADH help with
Osmoregulation by increasing the amount of water being absorbed back into the blood
What is Aldosterone
A steroid hormone produced by a the Adrenal glands
What is the role of Aldosterone
To control the concentrations of sodium ions in the body
What happens if too many sodium ions are absorbed and retained
High blood pressure may revelop
What is the concentration of sodium ions linked to
The balance of water and the regulation of blood pressure
When is the secretion of aldosterone triggered
When blood levels are low causing a drop in osmolarity
When blood volume is low causing low blood pressure
Functions of Aldosterone
Reabsorbs sodium ions returning them to the bloodstream
Water follows the sodium ions, increasing blood volume n blood pressure
When is homeostasis maintained
As the sodium ion balance is restored and blood volume increased
What is Diuresis
The increase in urine output
What are diuretics
Chemicals that cause you to pee
How is Caffeine a diuretic
It causes vasodilation which increases the filtration volume
How is Alcohol a diuretic
It inhibits the release of ADH which results in the volume if urine increasing
What is diabetes insipidus
Producing large quantities of dilute urine due to little ADH being secreted
What happens if the Kidney fails
Nitrogenous waste can’t be excreted and the pH, concentration of ions & water balance isn’t regulated
What causes kidney failure
Kidney stones, Infection due streptococcus bacteria and parasite schistosoma
What are kidney stones
Caused by crystal of salts solidifying into renal calculi
What causes Kidney stones
Too much calcium
Little water intake
Alkaline or acidic urine
Trauma
Injury caused by an external force
What are the types of trauma
Blunt force trauma
Penetrating force trauma
What is Blunt force trauma
Like a direct blow to the abdomen
What is the best indicator of a Blunt Kidney Injury
Haematuria- blood in the urine
What is a Penetrating force trauma
When the skin is broken or more severe
What is Dialysis
The movement of molecules between two solutions of different compositions down their concentration gradient
What does Dialysis do
It’s a short-term fix to kidney failure where blood is cleansed artificially
Disadvantages of Dialysis
Treatment is time consuming
Machine is expensive
Can only remove a certain amount if excess fluid
What is peritoneal dialysis
It uses the patient’s peritoneum as the dialysing membrane
It’s less efficient but more convenient as it can be done at home
What is a long term solution to kidney failure
Kidney transplant
Why it’s sometimes hard to get the kidney needed
Donor could not be registered
Tissue n blood type of donor and recipient not compatible
Disadvantages of transplants
There’s still a chance the kidney will be rejected
Cortisones( anti inflammatory) help prevent rejection but increased the risk of infection
Where ADH found
In the Pituitary glad
When is the secretion of Aldosterone triggered
When blood volume is low
When blood volume is low
What happens when the kidneys fail
Toxic nitrogenous wastes will not be excreted
pH, the concentration of ions and water balance of the body will not be regulated
What is the sodium pump
Sodium ions being actively transported out of the filtrate in the ascending limb into the tissue fluid surrounding the limbs.
What happens if you’re dehydrated
ADH is secreted, making walls pourus allowing water to be reabsorbed into the blood in order to hydrate you
What does Aldosterone do in the distal convoluted tubule
It cause Sodium and Chloride to be reabsorbed and sometimes small amounts of water
