Week 13: The Urinary & Excretion System Flashcards
Define excretion
The process of removing waste products and water from the body
What does excretion help to maintain?
Maintains homeostasis
What are some of the structures of excretion?
- skin
- intestines
- kidneys
- associated structures (bladder, ureters, urethra)
How does the skin carry out excretion?
Via the sweat glands, these produce sweat containing:
- salt
- excessive oil
- water
What does sweating help to do?
Cool the body during evaporation as well as flush out toxins and excess minerals from the body
What does the digestive system do?
Nutrition is absorbed by the blood to release energy in presence of oxygen (assimilation)
What can be formed in assimilation?
Many harmful products get formed, which are then removed via excretion
What is the primary function of the kidneys
To regulate the composition and volume of body fluids, and provide a constant internal environment for the body
What are the structural parts of the kidneys
- two kidneys which secrete urine
- two ureters which transport urine from the kidneys to the bladder
- a bladder where urine collects and is temporarily stored
- one urethra, where urine is discharges out of the bladder via the body
Where is the location of the kidneys?
The posterior wall of the abdomen, either side of the spine between T12 and L3
What are the two main parts of the kidneys?
- outer cortex
- inner medulla
What is the appearance and function of the outer cortex?
- reddish brown
- where fluid is filtered from the blood
What is the appearance and function of the inner medulla?
- paler in colour
- made up of renal pyramids
- some materials are selectively reabsorbed into the blood stream
What is the function of a nephron?
- filters impurities and metabolic waste from the blood
- maintains normal pH of the blood
- formation of urine
- regulation of salt and water in the body
Define water balance
Water intake and output must be equal in order to maintain a constant internal environment
How do we intake water?
- through digestion
- through metabolic activities
How is water output?
- urine
- alimentary canal
- sweat
- exhaled breath
What are some factors that affect fluid balance?
- increased body temperature
- increased salt in diet
- emotions
- blood pressure
What are the associated structures?
- bladder
- urethra
- ureters
What is the bladder?
A hollow organ that stores urine from the kidneys before disposal by urination
What is the location of the bladder?
Sits on the pelvic floor
What type of organ is the bladder?
A distensible organ
What is the function of the bladder?
Urine enters the bladder via ureters and exits via urethra, holding between 300-500ml before the urge to empty
What are the ureters
Tubes made of smooth muscle that propel urine from the kidneys from the bladder
How long are ureters in adults?
20-30cm long
3-4mm in diameter
What is the ureters lined with?
Lined by urothelial cells, a transitional type of epithelial, and has an additional smooth layer that assists with peristalsis in the lower 3rd layer
What is the urethra?
A tube that connects the runaway bladder to urinary meat is from removal of urine from the body
What do males use urethra for ?
Urinating and ejaculation
What does urethra in females used for?
Urinating
What do some colours of urine tell us?
- too dark is dehydration
- brown indicated bleeding from the kidneys
- high levels of glucose suggests diabetes
- low or no glucose indicated hypoglycaemia
