Genitourinary System Flashcards
How any types of HPV are there, and how are they transmitted?
200 types, 40 types are transmitted sexually.
Can be high or low risk
How prevalent is HPV, and how is it typically treated?
80% of sexually active people come into contact with it.
Normally cleared within 8 months to 2 years.
People unable to clear it are at increased risk of pre-cancerous changes. Onset of tumours is typically 13 years
Describe the histological layout of cells at the cervix.
Cervical opening (cervical os), surrounded by endocervix (simple granular cuboidal cells containing musin) , then the ectocervix (squamous, stratified, only base layer should have evidence of cell division)
How does HPV enter the cervical cells to cause disease?
Abrasions to the ectocervix exposing basement membrane, where HPV cells can then enter cellular DNA
What are koilocytes?
The ectocervical cells in which HPV has caused changes.
Hallow appearance around nuclei, enlarged/multiple nuclei, raisenoid appearance
Define high risk HPV infections
Viral DNA is incorporated into the host genome
Contain viral E6 and E7 proteins responsible for reactivating cell cycle in layers above basement layer
Cause persistent infection, proliferation of epithelial cells, and precursor legions (CIN and CGIN)
Subtypes 16, 18, 31, 45, and more
Define low risk HPV infections
Result in free viral DNA within cell
Cause vaginal warts
i.e. 6, 11, 42, 44
What is CIN?
Cervical Intraepithelial Neoplasia
CIN1- typically resolves itself, monitoring needed. bottom (closest to basement membrane) 3rd of squamous epi.
CIN2- involves bottom 2 3rds of squamous epi. Being tested for in screening.
CIN3- precursor lesion for squamous cell carcinoma, what is being testing for. Involves full squamous epi layer. Typically takes 2 years to develop into invasive carcinoma.
What is CGIN?
Cervical Glandular Intraepithelial Neoplasia
Less common than CIN
Precursor lesion to adenocarcinoma
Endocervical epithelium
What outcomes are possible with cervical screening?
Fail- insufficient cells, retest in 3 months
Negative- Come back in 5 years
Positive- sample tested for cytology
What cervical cytology tests are used in labs and how does it work?
Thinprep process 1. Dispersion 2. Cell collection 3. Cell transfer This is not diagnostic.
What is dyskariosis?
Abnormal cell with enlarged nuclei
Graded from mild (CIN1), moderate (CIN2), and severe (CIN3), depending on nuclei size
Appear to have enlarged nuclei with irregular borders, smaller nucleus to cytosol ratio, darker blue, non-circular
What is colposcopy?
Examination of cervical cells within patient using microscope and speculum
Can use acetic acid to highlight abnormalities.
Can take biopsies to determine diagnosis
How many women in Scotland will develop breast cancer?
1 in 8
women 50-70 are invited to screening
What type of cells and tissue are found in breasts?
Centre has central ductal structure, with lobular structures surrounding it. This is the breast tissue, it’s surrounded by fibrous pale pink tissue, and lastly adipose, white tissue cells .
Each duct lined by two layers, inner are tall cuboidal cells, no mitotic activity, surrounded by basal layer which can be fragmented, with subtle smaller cells outside the ducts
What is pleomorphism?
Different appearance of the same cancer
What is the prevalence of bowel cancer in Scotland?
3rd most common, 4000 new cases every year, typically people over 50
5 year survival around 60%
What is involved in the bowel cancer screening?
50-74 years invited.
Faecal Immunochemical Test (FIT)
Tests for haemoglobin (most cancers cause bleeding)- if greater than 80ugHb/g.
1 in 50 are referred on for colonoscopy.
What are superficial and deep nephrones?
Nephrons live in the cortex of the kidney, but loop of Henle extends down into the medulla.
Superficial nephrons and juxtamedullary nephrons,
Juxtamedullary nephrons have loop which extends much more deeply into renal medulla and are better at water reabsorption
What drives ultrafiltration?
High pressure
Pushes 20% of blood fluid into nephron.
Filters 1.25L of blood/minutes, filtering ~90-140ml/min out of the blood flow into the nephrons.
What is active secretion in nephrons?
Active pumping into the tubules to excrete substances, like drugs, faster than blood is being filtered.
What is the filtration barrier in nephrons? Move from capillaries into Bowman’s capsule
Formed elements are unable to move through fenestrations in glomerulus capillaries.
Basement membranes contain negative charge (heparin sulphate glycosaminoglycan, draws positive molecules) and collagen 4/ laminins (lamina densa)
Simple squamous cells and podocyte cells.
Podocytes give off processes (nephrins) which interdigitate with each other, helping to filter blood.
What sort of compound are filtered at the renal corpuscle?
Small molecules, ions, urea, glucose, amino acids, small proteins (haemoglobin would find it a tight fit, but charge of it will keep it in blood)
How can filtration go wrong?
High pressure pushes large molecule through.
Inflammatory disease causing podocyte processes to move further apart allowing larger molecules to be filtered.
What is a normal glomerular filtration rate?
90-140ml/min
Discuss the membrane, solute movement, and volumes present at the Proximal Convoluted Tubules.
Continual epithelial cells
Brush border to increase surface area
Active reabsorption of glucose, amino acids, co-transport of Na, and K ions.
Channels allow high amounts of water reabsorption
Co-transporters, aqueous channels, and membrane pumps responsible for movement.
At end of PCT, complete reabsorption of glucose / amino acids, substantial Na reabsorption and water.
Volume of filtrate by end is reduced by 2/3ds (about 40ml left)
Describe solute movement and membrane thickness within the Loop of Henle.
Thin membrane
Contains thin descending mechanism, and a thick wall for the ascending membrane due to solute pumping which creates counter-current mechanism that ‘recycles’ solutes.
No net reabsorption because solutes being pumped out enter into descending tubule of loop.
What is the significance of the ascending portion of the loop of Henle?
Solute pumping out of filtrate, like Na and Cl
Thicker membrane
Creates recycling of solutes, and osmotic pressures.
Describe the distal convoluted tubule, including its membrane, purpose, and how it differs from the proximal convoluted tubule.
Relatively thick walls with no brush border.
Similar job to proximal tubules, but at smaller level.
No glucose transporter.
Less electrolytes/water reabsorption.
Ion pumping is controlled by hormones, meaning Na and K exchange can be fine tuned.
What important features are found in the collecting duct in relation to water flow?
Not very active cells. Largely water proofing, but this is controllable.
Collecting duct moves down past loop of Henle where there is high osmotic pressure, causing final withdrawal of water.
Permeability is controlled by anti-diuretic hormone (AVP),
How does Anti-Diuretic Hormone/ AVP control water movement?
Aquaporins are made and stored in cell, they will be inserted into luminal membrane following anti-diuretic hormone (AVP) release, which will allow for water reabsorption of collecting duct.
Can have rapid insertion/removal of them.
What is diaresis and how is it impacted by hormones?
Increased urine production
Starts 15-20 minutes following ADH/AVP is released (when hormone half-life is reached), removing aquaporins from luminal membrane, causing filtrate to move straight to bladder
What is typical osmolarity of normal plasma?
300 mOsm (in textbooks may say 275-290)
What happens in regards to hormone release if plasma osmolarity is high?
Is rises, detected by osmotically sensitive cells in hypothalamus, causing increase in ADH/AVP secretion from the anterior pituitary gland. (i.e. makes more concentrated urine).
ADH causes more insertion of aquaporins within collecting duct, allowing for more water reabsorption.
What is the maximum concentration and max/minimum output of urine?
~1200mOsm
1mL/sec minimum
20mL/sec
What is the half life of ADH?
15-20 minutes
What is the juxtaglomerular apparatus?
Collection of cells within the distal convoluted tubule (where the tube curves back to meet the glomerulus) and glomerulus that sense hypo-filtration and can begin secretion of renin
How does renin influence blood pressure?
It splits angiotensinogen into angiotensin 1, which is later converted into angiotensin 2, which causes vasocontraction, resulting in increased blood pressure.
How does the sympathetic nervous system work within the kidney?
Sympathetic nerve innervation can activate the angiotensin/renin system to enhance its effectiveness and increase vasoconstriction.
What is aldosterone?
Steroid hormone that increases when electrolyte concentrations fall.
Makes additional sodium pumps in cells, resulting in increased reabsorption of Na within the loop, distal convoluted tubule, and duct cells
What secrete aldosterone?
The glomerulosa cells of the adrenal cortex
What ions does aldosterone influence?
Increases Na reabsorption
Increases Cl reabsorption
Secondary action- Increases K secretion (it swaps it for sodium)
Increases absorption of Na from gut, and reduced secretion of Na in sweat and tears
How does urine move along the ureter?
Peristalsis at about 1-2mm/second
How is urine flow from bladder regulated?
Sphincters
What is a cystometrogram?
Measuring the functioning of the bladder.
Looking at pressure and filling of it
What does the bladder consist of in terms of anatomy?
Smooth muscle, within the wall it is called detrusor muscle.
More internally is a water-proof mucosal lining, internally is the ureteral orifice.
Trigone
Internal urethral sphincter (neck)- smooth muscle
External urethral sphincter
What are the pressure phases of micturition?
Storage and voiding
How do pressures change during storage phase of micturition in the bladder and sphincter/urethra?
Bladder- pressure very slowly increases during storage phases
Sphincter- pressure is already slightly higher than the bladder, but also slowly increases during storage.
Sensory neurons start to pick up on bladder stretching, which signals contraction of external sphincter in later storage.
Are the bladder muscles and sphincters contracted or relaxed during the storage phase of micturition?
Bladder is relaxed
Inner urethral sphincter is contracted
During later half of storage phase, external sphincter is contracted
Stimulation of what receptor would be used in treating incontinence?
Beta 3
B3 agonists cause relaxation of the detrusor muscle, allowing for bladder to fill more, increasing its capacity.
What are the nerve roots on the pudendal nerve?
S2-S4
The sympathetic nervous system acts on the inner urethral sphincter using what receptor?
Noradrenaline on an alpha 1 receptor.
This will stimulate contraction, and a lack of urinary flow