SUGER Flashcards
How much of cardiac output do the kidneys receive and through which arteries
- about 1/5 of cardiac output
- through the renal arteries that arise directly from the abdominal aorta
What hormones do the kidney produce and what do these hormones do
- erythropoietin for control of red blood cell production
- renin for regulation of water and salt concentration
Describe the cortex and medulla of a kidney
- cortex is pale
- medulla is dark
- kidney contains 10 to 15 medullary pyramids whose apices point towards the hilum of the kidney
- cortex contains all of the glomeruli of the kidney and convoluted (coiled) parts of the proximal and distal tubules, first parts of collecting ducts
- medullary pyramids contains straight portions of the proximal and distal tubules, loops of Henle and distal part of collecting ducts
Describe the blood supply of the kidneys
-abdominal aorta
-renal artery (at L1)
-anterior and posterior division
-interlobar artery
-arcuate arteries (at the cortico-medullary junction)
-interlobular arteries (penetrate and divide cortex into lobules)
-afferent arterioles
-efferent arterioles (renal corpuscle)
-peritubular capillaries
descends into medulla
-vasa recta
-renal veins
-inferior vena cava
Where is blood filtered in the kidney and how
- in the glomerulus
- the glomerulus is made up of fenestrated capillaries ensheathed by podocytes
- the basement membrane between the endothelial cells of the capillaries and the podocytes of the epithelium constitutes the filtration barrier of the kidney
Where are the mesangial cells found
-between the coiled loops of the glomerular tuft
What do mesangial cells do
- they provide structural support for the kidney
- they have smooth muscle which contract and tighten capillaries to reduce the glomerular filtration rate
- produce matrix
- phagocytosis of glomerular breakdown products
Where are macula densa cells found
In the distal convuluted tubules
Where are the renin producing cells of the kidneys found
-the afferent arteriole
What do the macula densa cells do
- they sense low sodium and chloride levels
- stimulate the juxtaglomerular cells in the afferent arterioles of the kidney to release renin
Under how many Daltons do solutes need to be to pass into the urinary space of the kidney as primary filtrate
-50,000 Daltons
Describe the structure of the proximal tubules
- prominent brush border
- complex invaginations on their baso-lateral membrane
- cuboidal epithelium
- eosinophilic cytoplasm
What occurs in the proximal tubules
- re-absorption of filtrate
- sodium and glucose are actively transported
- protein and polypeptide uptake by endocytosis
- contain lysosome that break proteins down
List 2 important proteins that normally pass from the blood into primary filtrate but are recovered (reabsorbed) by the proximal tubule
- albumin
- haemoglobin
- almost any small negatively charged protein
What does the loop of henle consist of
- thick straight descending portion
- thin loop
- thick ascending portion
What does the thin ascending portion of the loop of Henle do
-retains water
-actively re-absorb chloride and sodium
So produces a dilute filtrate (urine) and a hypertonic interstitium (liquid in surroundings)
-vasa recta run alongside these tubules
What is the difference between the permeability of water in the thin descending and ascending loop of Henle and what does this cause
- the thin descending limb has low permeability to ions and urea but is highly permeable to water
- the thin ascending limb is not permeable to water but is permeable to ions
- this creates a concentration gradient within the renal medulla
Describe the distal tubules
- contains macula densa cells
- few short microvilli but no brush border
- cells often appear paler stained than those of proximal tubule
- deep invaginations on basal plasma membrane
- lots of mitochondria
- cuboidal epithelium
What do the distal tubules do
- under influence of aldosterone, sodium ions are reaborbed and potassium ions are excreted
- bicarbonate ions are re-absorbed and hydrogen ions excreted making urine acidic (through cellular carbonic anhydrase)
-acid/base balance and concentrations of urine
Which structures are known as medullary rays
The collecting ducts (and apparently the thin parts of the loop of Henle)
How does anti-duiretic hormone (ADH) affect the collecting duct cells
- increases permeability to water
- more aquaporins insert into its membrane and reabsorb water back
What is special about collecting ducts cells of the kidney
-dark intercalated cells with high concentrations of mitochondria
What structures make up the juxtaglomerular apparatus
-Apparantly just afferent arteriole and distal convoluted tubule but keep the ones below in mind
- afferent arteriole
- efferent arteriole
- macula densa
- lacis cells (specialised cell of the glomerular matrix)
Where in the body is angiotensin 2 produced
Renin secreted by modified muscle cells in the walls of the afferent arterioles of the glomerulus catalyses the conversion of angiotensinogen that is produced by the liver into angiotensin I. This is converted to angiotensin II mainly in the lungs. This goes on to stimulate the release of aldosterone by glomerular cells in the cortex of the suprarenal gland. This in turn promotes the reabsorption of sodium and water from the glomerular filtrate mainly by the cells of the distal tubule and collecting ducts.
Which cells of the kidneys are particularly responsive to aldosterone
Cells of the distal tubule and collecting ducts
-aldosterone promotes re-absorption of sodium ions and water thereby concentrates the urine and conserves body fluid
Which lipid are the membrane plates of the umbrella cells of the bladder rich in
-cerebrosides
Describe the epithelium of the bladder, ureters and urethra
- umbrella cells (can be binucleate)
- pseudostratified squamous epithelium (between 3 to 8 layers)
How are umbrella cells joined together
- thick membranes plates joined by thinner membrane bands
- the thick membrane plates are made of cerebrosides
What shape is the lumen of the ureter
-star shaped
Give the 3 points at which the ureter is sharply constricted and why is this important
- at its origin in the pelvis of the kidney
- as it passes into the true pelvis anterior to the sacro-iliac joint
- as it enters the postero-inferior surface of the bladder
A site where kidney stones are commonly lodged
How many layers of smooth muscle surround the epithelial tube of the ureter
-two helical layers of smooth muscle
Basically opposite to GI tract
-inner longitudinal layer
-outer circular layer
-no serosa
Describe the muscles neck of the bladder
- 3 distinct layers of muscle
- the innermost longitudinal layer projects inferiorly and turns transversely to form a sphincter around the prostatic urethra (male) and the external meatus (female)
Which muscle layer of the bladder forms the sphincter around the urethra
the innermost longitudinal layer projects inferiorly and turns transversely to form a sphincter around the prostatic urethra (male) and the external meatus (female)
How many parts is the male urethra divided into and name them and which epithelium they are covered by
3
prostatic, membranous and penile urethra
-prostatic (urothelium)
-membranous (urothelium)
Both Penile uretha below
- proximal bulbous (psuedostratified)
- distal pendulous (stratified squamous)
How do the epithelium of the male and female urethra differ
The male urethra (20cm) is longer and is covered by urothelium with mucous glands all along its lengths
The female urethra (4 to 5 cm) is covered by stratified squamous epithelium punctuated by areas of mucous glands (paraurethral and periurethral glands open into the urethra)
In both male and female, a striated voluntary muscle sphincter surrounds the membranous part of the urethra (derived from the muscles of the pelvic diaphragm)
What kind of tissue lies under the prostatic urothelium
-dense fibrous connective tissue that will restrict the distension of urothelium
How does the human kidney differ histologically from that of a smaller mammal such as a mouse or rat?
It is a compound kidney rather than a simple kidney which is the case with small mammals. A simple kidney has a single medulla with a single surrounding cortex. A compound kidney is, in effect, many simple kidneys in the same bag, with multiple medullary zones each surrounded by cortex. The human kidney consists of between 15 and 20 simple kidneys fused together with primary and secondary calyces draining into a single renal pelvis.
How is blood flow through the glomerulus regulated?
It is regulated by constriction of the afferent and efferent arterioles.
Contraction of smooth muscle in glomerulus tightens capillaries and reduces the glomerular filtration rate (part of tubular glomerular feedback)
Which do you think is more tightly coiled, the proximal convoluted tubule or the distal convoluted tubule?
Apart, obviously, of the straight portions of these tubules, the proximal tubule is more tightly coiled than the distal tubule. This results in more transverse and fewer oblique sections through proximal tubules than through distal tubules.
Why do the loops of Henle differ in length from one nephron to another?
This depends on the point of origin of the nephron. Nephrons whose glomeruli originate close to the surface of the kidney (outer cortex) have short loops of Henle that project only as far as the outer reaches of the medulla whereas those nephrons whose glomeruli arise close to the medulla have long loops that project deep into the medulla.
Why is the wall of the ureter composed mainly of smooth muscle rather than of fibrous connective tissue?
The muscular wall or the ureter undergoes peristaltic contraction that helps to conduct the urine to the bladder.
Which nerve tract supplies the muscle in the wall of the urinary bladder and causes it to contract during micturition?
Micturition occurs once the external sphincter of the bladder is relaxed (sympathetic stimulation) and the muscle wall of the bladder (detrusor muscle) contracts (parasympathetic stimulation)
Which glands drain into (a) the prostatic urethra and (b) the penile urethra?
Many of the genital glands drain into the prostatic urethra including the prostate itself, the seminal vesicles and the deferent duct (sperm). The bulbo-urethral glands and other smaller mucous glands drain into the membranous and penile urethra.
What type of epithelium lines the distal end of both the male and female urethra?
The distal ends of both the male and female urethra become lined by a stratified squamous epithelium.
What do mesangial cells do
- phagocytosis of glomerular basement membrane breakdown products
- provide structural support
Give the 3 layers of the glomerular basement membrane
- glomerular capillary wall
- basement membrane
- foot processes of the podocytes
A normal basement membrane has a lamina lucida and a lamina rarer, what does a glomerular basement membrane comprise of
- lamina lucida inturna
- double thickness lamina densa
- lamina lucida externa
- basically to basement membranes back to back
- contains negatively charged heparinsulfate molecules
What does the glomerular basement membrane contain that repulses negatively charges particles
-negatively charged heparinesulfate molecules
Loss of which two proteins in podocytes are associated with glomerular diseases
- defect in gene that produces nephrine causing cogentinal nephrotic syndrome
- defect in gene that produces CD2AP causes focal segmental glomerular sclerosis
What do granular cells do
- located in afferent arteriole
- sense blood pressure changes and secretes renin in response
Describe the epithelium of the thick sections of the loop of Henle
-cuboidal epithelium
Describe the epithelium of the thin sections of the loop of Henle
-simple squamous epithelium
Describe the epithelium of the collecting duct and what it does
- cuboidal epithelium
- contains principal cells that respond to aldosterone and anti-durietic hormone (ADH)
- contains intercalated cells that exchange hydrogen ions (excreted) for carbonate ions (reabsorbed)
Mutation of the aquaporin 2 gene leads to which hereditary disease
-diabetes insipidus
Which part of the kidney is prone to ischemia and why?
-loop of Henle as it is supplied by the vasa recta which is quite far from the glomerulus
Give the layers in the bladder epithelium
- urothelium
- lamina propria
- poorly defined muscularis mucosa
- submucosa
- muscularis propria
- subserosa and serosa
- functional valve to prevent reflux of urine into ureter
What do leydig cells do and where are they found
- produce testosterone
- in between tubules of seminiferous tubules
What do the rete testis do and where are they found
- they transfer sperm to the epididymis
- they connect the seminiferous tubules to the epididymis
What do the seminiferous tubules do and where are they found
- produce sperm
- found in the lobules of the testis
What type of epithelium lines the seminiferous tubules
-stratified epithelium consisting of Sertoli cells and cells of the germ line (developing spermatozoa)
How do sperm develop in the seminiferous tubules
- cells at the periphery of each tubule has germinal epithelium that produces large cells with speckled chromatin within their nuclei know as spermatogonia
- spermatocytes develop from these spermatogonia
- spermatocytes cross the blood-testis barrier created by the Sertoli cells
What do Sertoli cells do and where are they found
- they are supporting cells that nuture the developing sperm
- they are found in the seminiferous tubules
How long does sperm production take
-64 days
What would be the consequence of failure of the blood-testis barrier?
- the individual might recognise his sperm as “non-self’ and raise antibodies against them
- antibodies would then destroy his sperm rendering him infertile
At what stage in development of sperm does the reduction division take place?
The first meiotic division during which the developing sperm go from being 2n (number of chromosomes) to 1n occurs when the primary spermatocytes become secondary spermatocytes.
Where in relation to the blood-testis barrier does this reduction division take place?
- it occurs on the luminal side of the blood-testis barrier where the developing spermatids are not in direct contact with the blood stream and they are therefore not detected by the individual creating them.
- this prevents the production of auto- antibodies that may well destroy the developing sperm.
What epithelium line the efferent ducts
- cuboidal epithelium (basal cells)
- ciliated and non ciliated columnar epithelium
What does the epididymis do and how long is it
- 5m long
- serves as a storage and maturation site for sperm
What epithelium lines the epididymis
- pseudo-stratified columnar epithelium
- also contains a thin layer of smooth muscle that becomes thicker as it approaches the vas deferens
What do the small basal cells in the epididymis do
- they support the stereocilia (tall columnar cells with long microvilli)
- re-absorb excess testicular fluid
- phagocytose damaged sperm and cell debris
- provide nutrients for waiting sperm
Describe the stereo-cilia of the epididymis? Why are they inappropriately named?
- they help to provide nutrients to the sperm stored in the epididymis.
- unlike true cilia they are not motile nor do they have a core of microtubules as true cilia do.
What is the epithelium of the vas deferens
- pseudo-stratified columnar epithelium
- has 3 layers of smooth muscle
During ejaculation, how is sperm transported in the vas deferens
- sudden and rhythmical contraction of its smooth thick muscle wall help to expel the sperm during ejaculation
- has microvilli too
At vasectomy, how would you differentiate between the vas deferens and other vessels running in the cord, (a) by gross appearance and (b) histologically?
- the thick muscular wall of the vas deferens provides more resistance to the touch (feels cord-like) and unlike the testicular artery is difficult to compress and has no pulse!
- histologically the two tubes can be differentiated by the thickness of the smooth muscle wall, which is much thicker in the vas deferens and composed of 2 distinct layers, and by the nature of the epithelial lining which is a pseudostratified one in the vas deferens but a simple squamous one (endothelium) in the artery
What does the seminal vesicles do
- when stimulated by testosterone
- the cells of the seminal vesicles enlarge and secrete a creamy opalescent fluid
- this fluid has an acid pH, rich in globulin, vitamin C, amino acids and sugars, notable fructose all nutrients for the sperm
- comprises 70% of the ejaculate
What hormone causes the cells of the seminal vesicles to enlarge
-testosterone
Contraction of the double layered capsule of the smooth muscle of the seminal vesicles at ejaculation expels fluid into the
-ejaculatory duct where it mixes with spermatozoa
What is the epithelium of the seminal vesicles
-pseudo-stratified columnar epithelium
What are the 3 layers of glands within the prostatic gland and where do they discharge into
- mucosal
- submucosal
- main
All discharge seperately into different part of the prostatic urethra
How does testosterone affect the prostate gland
- the cells of the prostate gland increase in height and secrete different digestive enzymes into urethra forming seminal fluid
- a digestive enzyme secreted is acid phosphatase
Which glands in a male secrete a watery galactose-rich secretion into the membranous urethra that precedes the main ejaculate
-bulbo-urethra glands
What do the bulbo-urethra glands in a male do?
-secrete a watery galactose-rich secretion into the membranous urethra that precedes the main ejaculate
Extreme resistance may be felt when trying to insert a catheter trans-urethrally into the bladder of a man. What histological structures may be the cause of this resistance?
- sometimes the tip of the catheter can be diverted into the blind‐ ended bulbo‐ urethral glands that discharge into the membranous part of the male urethra.
- the shorter and straighter female urethra does not normally pose the same problem.
How does an erection occur
- the erectile compartments are fed by the helicine branches of the pudendal artery
- in a flaccid state, arterio-venous shunts direct the blood away from these arteries
- parasympathetic stimulation closes the arterio-venous shunts diverting blood into the erectile compartments which become turgid with blood causing an erection
Describe the skin covering the penis
- most of the penis is covered in hairy keratinising stratified squamous epithelium
- except the prepuce (foreskin) and glans penis which are covered in lightly keratinising stratified squamous epithelium
In what way does the epithelium inside the prepuce (foreskin) differ from that of the rest of the penis and what consequence does this have for disease processes?
- the epithelium on the inside of the prepuce is nominally a stratified squamous (keratinized) epithelium. It is however very thin and very lightly keratinized.
- it is therefore rather prone to the ingress of invading organisms.
- it is a prime site for the uptake of HIV and it has been shown that circumcision greatly decreases the entry of this virus mainly because the remaining and exposed epithelium becomes much more heavily keratinized.
Erection and ejaculation are separate but interlinked processes. How are these processes controlled neuronally and which anatomical nerves are involved?
- parasympathetic nerve (pelvic splanchnic nerves) = erection
- sympathetic autonomic nerve (hypogastric plexus from the terminal part of the sympathetic chain) = ejaculation
Think “Point and Shoot”
Which erectile compartment/s is/are the least rigid during an erection, and why?
- the two corpora cavernosa usually become more rigid than the corpus spongiosum. (As the name suggests the corpus spongiosum is spongier).
- the penile urethra passes through this compartment and therefore is less liable to be compressed than if it were to pass through the more rigid compartments, thus ensuring the passage of seminal fluid during ejaculation.
Give the average weight of the testis
15-19g
Give the 3 layers of the capsule surrounding the testis
- tunica vaginalis (flattened layer of mesothelial cells)
- tunica albuginea (collagen fibre with fibroblasts, myocytes and nerve fibres)
- tunica vasculosa (loose connective tissue containing blood vessels and lymph)
Give the 3 types of spermatogonia
- Type A (dark staining stem cells (Ad) and pale staining stem cells (Ap))
- Type B
Describe the parts of a spermatozoa (sperm)
- head (acrosomal cap and nucleus)
- midpiece (spiral mitochondria)
- tail (neck - centrioles, axoneme and plasma membrane)
What is special about the histology of Leydig cells
- they contain Reinke’s Crystalloids
- which are not seen before puberty and become more common with increasing age
What epithelium lines rete testis
-ciliated simple columnar epithelium
Give the lobes of prostate gland
- anterior
- middle
- posterior
- 2 lateral lobes
Which part of the prostate gland is a common site for cancer and which part is commo to increase in age
- peripheral zone is a common site for prostate cancer
- central zone increases with age
What do the secretory cells located on in the luminal side of the acini glands in the prostate secrete
-PSA prostate specific antigen (an enzyme used to liquidify semen after ejaculation) and PAP into the seminal fluid
What does the stroma of the prostate contain and why is it important
- contains smooth muscle, blood vessels, fibroelastic fibres and nerves
- it is important because it usually undergos hyperplasia with increasing age (common in a condition called benign prostatic hyperplasia)
Give the steps of differentiation into the male reproductive system
- XY chromosomes
- encodes the SRY gene
- promotes testis-determining factor
- genital ridge develops into testis
- leydig cells secrete testosterone
- mesonephric duct development
- sertoli cells secrete mullerian-inhibiting factor
- degeneration of the paramesonephric ducts
Give the steps that lead to the development of female reproductive system
- XX chromosomes
- no gonadal hormone influence
- genital ridge develops into ovarian tissue by default
- abscene of testosterone
- mesonephric ducts degenerate
- absence of mullerian-inhibiting factor
- paramesonephric ducts develop
Describe the major complications of chronic renal failure
- anaemia
- Gout
- Heart failure
- Stroke
- Hyperkalemia (high potassium)
- Metabolic disorder like osteodystrophy (slow bone growth or weak bones due to low calcium and phosphorus levels in the blood), inflammation and dyslipidemia (abnormal levels of lipid in the blood)
List the common causes of chronic renal failure
- diabetes (high blood sugar damages the blood vessels of the kidney)
- high blood pressure (damages blood vessels in the kidney)
- polycystic kidney disease (genetic condition that causes growth of cysts in the kidneys)
- lupus (lupus nephritis) leading to glomerulonephritis (inflammation of glomeruli and nephrons)
- recurrent kidney infections
- Good pasture syndrome (damages the kidney membranes)
List the causes of acute kidney injury and classify as pre-renal, renal or post-renal.
-acute kidney failure is where the kidneys suddenly stop working properly, can range from minor loss of kidney function to complete kidney failure
Pre-renal (when the blood flow to the kidney is impaired)
- low blood volume (blood loss, excessive vomiting, diarrhoea or severe dehydration)
- heart disease (heart pumping out less blood)
- liver failure (heart pumping out less blood)
- sepsis (heart pumping out less blood)
- medication like aspirin and ibuprofen
- overuse of non steroidal antiinflammatory drugs (NSAIDs)
Renal (damage to the kidney)
- blood clot in the kidney
- Kidney infections
- Chemotherapy drugs and antibioics
- Hemolyic uremic syndrome
- Glomerulonephritis (inflammation of the glomeruli -the kidney filters)
- Blood vessel inflammation or vasculitis
Post-renal (urinary obstruction)
- colon cancer
- prostate cancer
- cervical cancer
- blood clots
Presentation and management of atopic eczema
- Atopic dermatitis is a chronic, itchy skin condition
- common in children but may occur at any age
- also known as eczema and atopic eczema and was formerly known as Besnier prurigo
- the most common form of dermatitis.
- usually occurs in people who have an ‘atopic tendency’ so may develop any or all of three closely linked conditions; atopic dermatitis, asthma and hay fever (allergic rhinitis)
- these conditions run within families with a parent, child or sibling also affected. A family history of asthma, eczema or hay fever is particularly useful in diagnosing atopic dermatitis in infants.
-Atopic dermatitis arises because of a complex interaction of genetic and environmental factors including defects in skin barrier function making the skin more susceptible to irritation by soap and other contact irritants, the weather, temperature and non-specific triggers
Presentation
- inflamed red, blistered weepy patches of skin
- in between flare ups, skin can look normal or have dry thickened and itchy areas
- common in folds of skin of the elbow and knees but can be anywher on the body
Management
- reduction of exposure to trigger factors where possible
- regular emollients (moisturisers)
- intermittent topical steroids
Common triggers for skin conditions
- harsh soaps and detergents
- coarse fibres (wool and synthetic) and seams in undergarments
- cosmetics and perfumes
- dusty environments
- prescribed and over the counter treatment crems
- stress
- cold and dampclimate
What are the ethical issues around self-prescribing/prescribing for friends and family
What does the GMC say about self prescribing
18 - you must not prescribe a controlled medication for yourself or someone close to you unless;
a. no other person with the legal rights is there to prescribe where a delay could put your life or patients life’s at risk or cause unacceptable pain
b. the treatment is immediately necessary to save a life, avoid deterioration in health or alleviate uncontrollable pain or distress
19 if you prescribe for yourself or someone close to you, you must
a. Make a clear record at the same time or as soon as possible giving relationship to patient and reasons you prescribes
b. tell you GP what medicines you prescribe (unless the patient objects)
What forms the filtration barrier of a nephron and how does it work
- formed by the basement membrane that has a charge that repels proteins and molecules larger than 50,000 Daltons
- the podocyte foot processes create physical pores
More than 3 grams of albumin a day in the urine is indicative of
-something wrong in the glomerulus
What does the alpha intercalated cells of the collecting ducts do
-secrete acid
What does the beta intercalated cells of the collecting ducts do
-secrete bicarbonate
what is an elderly primigravida
The elderly primigravida is defined as a woman who goes into pregnancy for the first time at the age of 35 years or older.
what three layers make up the skin
epidermis, dermis and fatty subcutis layer
when does the breast become fully functional
during pregnancy
is the breast a sweat gland
yes
what is the mucosa of the epidermis
stratified squamous keratinising epithelium
list the 4 main layers of the epidermis
- layer of dead keratinised squames (stratum corneum)
- granular layer with cells containing keratohyaline granules (stratum granulosum)
- spinous layer (thickest layer) (stratum spinosum)
- germinative layer (stratum basale)
list the 2 parts of the dermis layer
the fibrous layer (rich in collagen and elastic fibres)
-papillary dermis few in collagen fibres
-reticular dermis rich in collagen fibres
the adipose layer (fatty layer)
which part of skin contains the root of hairs cell, sweat glands and sensory nerve endings
the dermis of the skin
where is the epithelium that forms the epidermis of the skin thickest and thinnest
thickest at the palms of the hands and the soles of the feet
thinnest on the some parts of the abdomen, thorax, lips, eyelids and external genitalia
is the skin on the palm of the hand and the sole of the feet hairless
yes
what are the keratohyaline granules a precursor for
keratin
what cells make up the majority of the epidermis
keratinocytes
where are keratinocytes derived from
germ cells within the germinal layer of the epidermis
apart from keratinocytes, what other cells are within the epidermis layer of the skin
melanocytes
where are melanocytes derived from
- the neural crest of the embryo
- they migrate into the epidermis during development
to which layers in the epidermis does the melanin from the melanocytes migrate to
the basal and prickle layer in the epidermis
does the number of melanocytes determine the colour of skin
no, all races have the same number of melanocytes
what determines the colour of skin
the amount of melanin stored in the keratinocytes is proportional to the colour of the skin
what prevents the skin from splitting when stretched
the desmosomes between the cells of the spinous (prickle) cells
what do the langerhan cells of the epidermis do
- they act as the antigen detecting cells as part of the immune response of the skin
- they increase with inflammation
what is the clinical significance of Merkels cells
they can give rise to a rare form of skin cancer
what do Merkels cells do and where can they be found
- in the basal cells of the epidermis
- they relay sensory information of fine touch
- they form nerve synapses with nerve fibres in the dermis
are hair cells from the dermis or epidermis
they are epidermal in origin
what is the glassy membrane
a thickened version of the basement membrane where hair root arises from
how does sympathetic innervation affect the erector pilli (smooth muscle)
causes it contract and stand on end
what are fingernails and toe nails made from
compacted keratin
how are fingernails and toenails produced
-they arise from nail matrix cells from the eponychium (cuticle)and can be seen through the lunula (pale crescent of cells)
the fold of skin under the distal edge of the nail is called
hyponychium
destruction of the nail matrix cells will result in permanent loss of
the nail
which sweat glands are most common
the eccrine sweat gland
how do the myoepithelial cells help with sweat glands
-the contractile cells help to expel the sweat
where are pheromone apocrine sweat glands found
in the armpits, around the anus and external genitalia
give a sensory nerve endings that is commonly found in the dermal papillae
meissner’s corpuscle
which dye is used on nerve fibres and stains black
osmium tetroxide
give two olaces that a pacinian corpuscle can be found
in the dermis of the skin
in the pancreas
give a sensory nerve endings that is commonly found in the dermis
pacinian corpuscle
give the mucosa of the conjunctiva
- two layers of cells
- stratified columnar epithelium cells
give an example of a large sebaceous gland of the eyelid
the meibomian gland
give an example of 4 smaller sweat glands of the eyelid
moll sweat gland
zeis (sebaceous) sweat gland
kraus and wolfring (accessory lacrimal) sweat glands
when do milk producing alveolar cells develop
during pregnancy
when do breast tissue develop
1 or 2 years before period starts at about 9 to 11 years old
what attach the breast to the chest wall and skin
suspensory ligaments of Cooper (thick fibrous strands)
how does milk travel from the breast tothe nipple
lactiferous duct to lactiferous sinus to nipple
what causes tenderness of the breast during the second half of periods
- fluctuating hormone levels
- lead to progesterone led oedema in breast segments causing tenderness and discomfort
what are montgomery’s tubercles
raised sebaceous glands in the areola surrounding the nipple core
how does high levels of oestrogen and progesterone affect lactation
they suppress lactation
how do lactating breasts develop in the 1st trimester of pregnancy
cortisol, growth hormone and oestrogen promote the proliferative phase of the epithelial cells
which hormones stimulate the full development of lactating breasts
prolactin, progesterone, human chorionic sommatomammotropin (hCs or human placental lactogen, hPL), adrenal corticosteroids and insulin
in the later stages of pregnancy what accumulates in the stroma of lactating breasts
lymphocytes and plasma cells
how are milk fats discharged from a lactating breast
apocrine process
how are milk proteins discharged from a lactating breast
merocrine process
Where in the skin do blisters most commonly form?
Blisters caused by abrasion normally occur and the dermal/epidermal interface.
Blisters caused by heat may occur at any depth and may involve the deeper layers of
the dermis.
What constitutes a mole?
Moles are formed from a dense aggregation of melanocytes and their attendant
keratinocytes.
Which hormone, when released into the blood stream induces the expression of milk during
breast-feeding?
Tactile stimulation of the nipple during suckling triggers the release of oxytocin by the
anterior pituitary. This causes the myoepithelial cells surrounding the secretory alveoli of the breast to contract and to help to expel the milk
where is the site of vitamin D synthesis
the skin
Where are melanocytes usually found
In the stratum basale (stem cells) layer of the epidermis
Where are melanin transported to keratinocytes in
Melanosomes
What hormones stimulates the production of melanin
MSH and ACTH
How does melanin protect us from non-ionising radiation damage
-it absorbs ultraviolet light
What layer lies between the stratum corneum and the stratum granulosum
Stratum lucida - faint pink layer (most prominent in the palm of the hands and soles of the feet)
What structure do sebaceous glands usually accompany
Hair follicles
How do sebaceous glands discharge their contents
Holocrine secretion (so the entire cell is lost and discharged)
What structures do aprocrine glands usually surround
Hair follicles
Armpit and groin
Anus and genitalia
Ceruminous glands in the ear
How do apocrine glands discharge
Apocrine secretion (cytoplasm that bud off the cell)
What structures are eccrine glands associated with
Found everywhere in the skin
Produce watery secretion
How do eccrine glands secrete their content
Eccrine (merocrine) secretion (exocytosis across the luminal surface of the cells)
They have inner secretory cell and outer myoepithelial cells too
What are Retes pegs
The ridges that the line between the epidermis and dermis found
-basically the wavy demarcation line
What is the dermis that is in between each retes peg called
The papillary dermis
Where can meissner’s corpuscle be found
Dermal papillae between the fingers, palms and soles
Are meissner’s corpuscle encapsulated or myelinated
They are encapsulated but unmyelinated nerve endings
How long are meissner’s corpuscle
30-140um long
What can of sensation are meisner’s corpuscle involved in
Fine touch
What kind of sensation are pacinian corpuscle involved in
Vibration and tickle
How long are pacinian corpuscles
1-4mm long
Where are pacinian corpuscle found
Deep dermis
What is the different of breast tissue in female and males
In males the breast tissue only comprises of the ducts
What is the functional unit of the breast
The terminal duct lobular unit
How are the ducts and lobule of the breast arranged
In two layers
An outer myoepithelial cell
An inner columnar epithelial cell
what is the daily folic acid recommendation for pregnant women
400 micrograms of folic acid from before pregnancy to until 12 weeks pregnant
family history of neural tube defects, diabetes, epilepsy and taking anti-retroviral medicine for HIV means the pregnant women have to take a higher dose 5milligrams
which vitamins are pregnant women advised not to eat too much of
vitamin A because it can cause developmental deformities
what advised are pregnant women given in regards to vitamins D and why
pregnant woman and all adults need 10 micrograms of vitamin D a day
vitamin D regulates the amount of calcium and phosphate in the body
what vitamins might vegan or vegetarian pregnant woman struggle to get
iron and vitamin B12
what foods are pregnant women advised to avoid
- soft blue cheeses
- soft cheeses with white rinds
- raw or partially cooked eggs (salmonella)
- pate (listeria)
- raw or undercooked meats (parasites causing toxoplasmosis an infection)
- unpasteurised milk and untreated water
- liver
- herbal remedy liquorice root
- alcohol
- high levels of caffeine
- swordfish, shark or marlin
preconceptual care and advice for pregnant women
- quit smoking if possibly
- take folic acid supplements
- avoid alcohol
- maintain a healthy weight
- if not, get flu and whooping cough vaccinations
- test for sickle cell and thalassaemia
what does the 8 to 14 weeks dating scan in pregnancy include
- ultrasound to estimate due date of the baby
- check the physical development of the baby
- screening for conditions eg downs syndrome
what does the 20 weeks scan in pregnancy include
- ultrasound to check physical development
- screening for HIV, syphilis and hepatitis B
- also offered the whooping cough vaccine again
what does the 34 scan in pregnancy include
-told about caesarean
-use tape measure to measure uterus
measure blood pressure and test urine for protein
-offered 2nd anti-D treatment if rhesus negative
what is a nulliparous women
Nulliparous is the medical term for a woman who has never given birth either by choice or for any other reason. This term also applies to women who have given birth to a stillborn baby, or a baby who was otherwise not able to survive outside the womb
how does the risk of Down’s syndrome increase with maternal age
1:1,500 at 20 years.
1:800 at 30 years.
1:270 at 35 years.
1:100 at 40 years.
>1:50 at 45 years and over.
when would chorionic villus sampling be offered for Down’s syndrome testing
if less than 13 weeks of gestation
carries a 1-2% risk of miscarriage