Week 9 Flashcards
How big are the kidneys?
Approximately 11cm long
Where are the kidneys located?
On the posterior abdominal wall, either side of the vertebral column, approximately at level T12 to L3.
Why does the right kidney lie slightly lower than the left?
The large right lobe of the liver restricts it superiorly.
What is the shape of the kidney?
The lateral margin of each kidney is smoothly convex, while the medial margin is concave, and further indented in the middle at the hilum.
What is the function of the hilum in the kidneys?
The renal vessels and the renal pelvis enter and exit the kidney.
What are the three layers of supportive tissue that cover each kidney?
The renal capsule, the adipose capsule and the renal fascia
What is the renal capsule?
A thin fibrous sac made of dense, irregular connective tissue that adheres closely to the kidney.
What is the function of the renal capsule?
It maintains the shape of the kidney and protects it from trauma and infection
What is the adipose capsule?
a layer of fat that surrounds the renal capsule of the kidney
What is the function of the adipose capsule?
It protects and supports the kidney
What is the renal fascia?
A layer of tissue that passes in front of and behind both kidneys. It is made of dense irregular connective tissue and attaches to the renal capsule by strings of fibres.
What is the function of the renal fascia?
It provides anchorage of the kidneys to surrounding structures
What is the renal cortex?
the outer 1 cm of the kidney that contains the arcuate and interlobular arteries and veins and cortical nephrons (except for parts of the loop of henle and the collecting tubules which descend into the medulla.
What function occurs in the renal cortex?
Ultra filtration
What are the renal columns?
Extensions of the cortex that project in between the pyramids of the medulla and help anchor the cortex.
What is the renal medulla?
The inner section of the kidney that lies deep to the cortex and contains the renal pyramid. The medulla appears striated as it contains the striated as it contains the tubular systems of the juxtamedullary nephrons, as parts of the loop of Henle and collecting tubules of the cortical nephrons
What are the renal calyces?
Renal pyramids drain into minor and major calyces which in turn empty into the renal pelvis, and ultimately, the ureter
What are the renal pyramids?
Cone shaped structures that terminate medially by protruding into the minor calyces. They appear striated because they are packed with bundles of nephron loops and collecting tubules, plus associated capillaries.
What is the renal papilla?
Where the tips of the pyramids protrude into the minor calyces. Here all the urine from the collecting tubules into the minor calyces.
What are minor calyces?
Cup like projections that surround the papilla of each pyramid. Several minor calyces converge to for a major calyce.
What are major calyces?
There are two or three in each kidney. They join to form the renal pelvis
what is the renal pelvis?
A single funnel shaped structure located centrally at the hilum of the kidney. it drains into the ureter
Outline the flow of urine?
Renal pyramid—papilla—minor calyces—major calyces—renal pelvis—ureter
What supplies blood to the kidneys?
Renal arteries arising directly from the abdominal aorta .
How much of the blood pumped out of the heart do the kidneys receive?
Since the kidneys are so important in the regulation of blood composition they receive roughly 20%
Where does the renal artery go?
It passes laterally from the abdominal aorta to reach the hilum of the kidney before branching into segmental arteries
Where do the segmental arteries go?
They branch from the renal artery and split into interlobar arteries
Where do the interlobar arteries go?
Pass through the renal columns
Where do the arcuate arteries go?
Leave the interlobar arteries at right angles to branch over the outer surface of the pyramid, forming an arterial anastamosis
How many renal pyramids are there?
8-10
What is an arterial anastomosis?
A connection between two arteries
Where do the interlobular arteries go?
They branch from the arcuate arteries to supply the cortex
What are the interlobular arteries also known as?
cortical radiate arteries
Outline the flow of blood into the kidneys?
Renal artery—segmental arteries—interlobar arteries—arcuate arteries—interlobular arteries—afferent arterioles
What are the afferent arterioles?
Each nephron receives one arteriole,which then divides again to form a plexus of capillaries of capillaries around the nephron
Outline how blood leaves the kidneys?
Efferent arterioles—arcuate veins—interlobar veins—renal vein
How big is the prostate?
Roughly 3cm in diameter
Where is the prostate situated?
Underneath the bladder, and it surrounds the beginning of the urethra
What travels through the prostate?
The prostatic urethra and ejaculatory ducts and open into the prostatic urethra
What is the prostate composed of?
Tubular alveolar glands supported by stromal connective tissue containing thick sheets of smooth muscle.
What are the functions of prostatic fluid?
-to aid sperm mobility
-aiding viability of sperm
-protects sperm against the acidic vaginal secretions
How many nephrons does each kidney have?
There is about 1 million in each kidney
What are nephrons?
The functional unit of the urinary system
What do nephrons consist of?
an intricate system of tubules surrounded by blood vessels.
What are the key functions of the kidneys?
Osmoregulation and removal of waste from the blood
What part of the nephron is found in the cortex?
The renal corpuscle
What is the renal corpuscle?
A tubular capsule wrapped around a tight network of capillaries
What comes after the renal corpuscle?
the renal tubule
What is the function of the renal tubule?
It connects the tubular capsule of the renal corpuscle to the collecting ducts that are responsible for gathering up the urine from several different nephrons
what are the segments of the renal tubule?
-proximal convoluted tubule (PCT)
-Loop of Henle
-Distal convoluted tubule (DCT)
What are the two types of nephrons?
cortical and juxtamedullary. Approximately 85% are cortical and 15% are juxtamedullary
What distinguishes between the two types of nephrons?
cortical nephrons have short loops of Henle whereas juxtamedullary nephrons have long loops of Henle which extend into the medulla
What is the glomerulus?
A compact network of capillaries
What is the glomerular capsule?
Also known as bowmans capsule, it surrounds the glomerulus
What happens between the glomerulus and the glomerular capsule?
Filtration of the blood
What is produced by the filtration of blood?
Glomerular filtrate
Where does the glomerular filtrate move to after its filtered?
It then enters the renal tubules for further processing before it can be called urine
What type of cells line the glomerulus?
The wall of the glomerulus consists of one layer of specialized epithelial cells which have many holes
What are the holes in the wall of the glomerulus called?
fenestrations
What are the two layers of the glomerular capsule?
The visceral and parietal layer
What is the visceral layer?
the innermost layer composed of highly specialised cells called podocytes
What is the parietal layers?
The outermost layer which forms the outer wall of the capsule
What is the gap in between the two layers of the glomerular capsule?
The capsular space. Once fluid has exited the glomerulus, it enters this space prior to moving into the PCT
Where does the fluid go after it has left the renal corpuscle?
It enters the renal tubule, which is divided into three main sections
What are the three main sections that the renal tubule is divided into?
The PCT, the loop of Henle and the SCT
Where is the PCT located?
The renal cortex.
What happens in the PCT?
A large proportion of solute and water reabsorption
Where is the Loop of Henle located?
Begins in the renal cortex and extends into the renal medulla before turning 180 degrees and re-entering the renal cortex
What happens in the Loop of Henle?
Water and some solute reabsorption, Active and passive reabsorption of sodium and water, Passive ion reabsorption. Impermeable to water. Significant quantities of Na+, K+, and Cl- are reabsorbed.
What does the DCT do?
Links the loop of Henle with the collecting ducts
What happens in the DCT?
Reabsorption of water, Na+, Cl-, and Ca2+ (early) Reabsorption of Na+, HCO3-, urea, and the facultative reabsorption of water. The secretion of K+ and H+. (late)
Where does the fluid go after the DCT?
The Collecting ducts
What are the collecting ducts?
Continuous with the DCT and function to drain the renal tubules
What happens in glomerular filtration?
blood flows from the afferent arteriole into the glomerulus, where pressure forces fluids and specific solutes to leave the blood and enter the glomerular capsule
What type of molecules are filtered?
Only small molecules travel with the fluid into the glomerular capsule to become part of the glomerular filtrate
What happens to molecules that remain in the blood?
Cells, and larger molecules with a diameter greater than 7 nm are prevented from entering the glomerular capsule by the filtration membrane, and are thus retained within the circulatory system and subsequently enter the efferent arteriole.
What are the two main categories that kidney dysfunction can be divided into?
Acute Kidney Injury (AKI)
Chronic Kidney Disease (CKD)
What is AKI?
An abrupt loss of kidney function within a few days
What is CKD?
A progressive loss of function of more and more nephrons that gradually decrease kidney function
What are the main categories of the causes of AKI?
Prerenal AKI
Intrarenal AKI
Postrenal AKI
What is Prerenal AKI?
Results from decreased blood supply to the kidneys. Reflects an abnormality originating outside the kidneys
What is Intrarenal AKI?
Results from abnormalities within the kidney itself including those that affect the blood vessels, glomeruli, or tubules
What is postrenal AKI?
results from the obstruction of the urinary collecting system anywhere from the calyces to the outflow of the bladder
When do clinical symptoms of CKD usually start?
When the number of functioning nephrons falls below 70-75% below normal
What are some possible causes of CKD?
Metabolic disorders, Hypertension, Renal vascular disorders, Immunological disorders, Infection, Primary tubular disorders, Urinary tract obstruction and congenital disorders
What is BPH
Benign prostatic hyperplasia, or, enlargement of the prostatic gland
What symptoms can this cause?
- Frequent or urgent need to urinate
- Increased frequency f urination at night (nocturia)
- Difficulty starting urination
- Weak urine stream or a stream that stops and starts
- Inability to completely empty the bladder
What cells undergo hyperplasia in BPH?
Glandular epithelium and the stromal cells (including muscle fibres)
What are possible causes of BPH (theories)
-Hormonal causes (different proportions of oestrogen to testosterone)
-DHT (dihydrotestosterone) (a male hormone that plays a role in prostate development and growth
-Ageing
What are risk factors of BPH?
Ageing, Family history, obesity, lack of physical activity and ED
What are the conditions for a screening programme?
-The condition should be an important problem for the individual and the community
-There should be an accepted treatment for patients with the disease
- Facilities for diagnosis and treatment should be available
- There should be a recognisable latent or early symptomatic stage
- There should be a suitable test or examination
- The test should be acceptable to the population
- The natural history of the condition, including development from latent to declared disease, should be adequately understood
- There should be an agreed policy on whom to treat as patients
-The cost of the case finding programme should be economically balanced in relation to expenditure on medical care as a whole
-Case finding should be a continuing process
- There should be quality assurance, with mechanisms to minimise potential risks of screening.
- The programme should ensure informed choice, confidentiality and respect for autonomy.
- The programme should promote equity and access to screening for the entire target population.
- The overall benefits of screening should outweigh the harm.
What is screened for in pregnant women?
infectious diseases, downs syndrome, pataus syndrome and Edwards syndrome, sickle cell diseases and physical abnormalities
What is screened for in new born babies?
physical examination, hearing test, blood spot test
What are examples of other screening programmes?
Diabetic eye screening, Cervical screening, breast screening, bowel cancer screening, AAA screening
Is there screening for prostate cancer?
No because PSA tests are unreliable and can give fals positive/ false negative results.
Describe what is recommended from the “eat well” plate
plenty of fruits and vegetables
plenty of starchy foods such as bread, rice, potatoes and pasta
some meat, fish, eggs, beans and other non-dairy sources of protein
some milk and dairy foods
just a small amount of foods or drinks that are high in fat or sugar
What is metabolism?
the sum of all chemical reactions in which energy is made available and consumed in the body
Give some uses of energy in the body
Contraction of muscle and hence for all movement
accumulation of ions and other molecules against concentration gradients
biosynthesis and hence for the building of tissues
waste disposal and hence for getting rid of the end products of bodily function
generation of heat and hence maintenance of body temperature
Describe ATP
It is often stated that ATP is the energy currency of living organisms, since hydrolysis to give ADP and Pi liberates large amounts of energy
In metabolism, ATP is continually made and broken down
How is glucose converted into Acetyl CoA?
glycolysis
How are fatty acids converted into Acetyl CoA?
beta oxidation
How are amino acids converted into Acetyl CoA?
transamination, oxidative deamination
What are the major common pathways that are the main producers of ATP?
TCA (Krebs) cycle
oxidative phosphorylation
Describe glycolysis
glucose is turned into 2 pyruvate
occurs in cytosol
ATP investment and ATP generation stages
Describe what happens to pyruvate in anaerobic conditions
pyruvate is converted into lactate, this regenerates NAD+ to keep glycolysis going
overall glucose + 2ADP +2Pi > 2lactate + 2 ATP
Describe what happens to pyruvate in aerobic conditions
pyruvate is transported to the mitochondria and converted to acetyl CoA by the action of pyruvate dehydrogenase
NADH produced
Describe the breakdown of fatty acids
released from triglyceride stores in adipose tissue via the action of lipase enzymes
transported in the blood as a complex with albumin and are taken up by cells for oxidation
They are then attached to CoA, driven by ATP and catalysed by acyl CoA synthase
Acyl groups are joined to carntitine which allows them to translocate into the mitochondria
In each reaction of the cycle the fatty acid is shortened by 2 carbon atoms, with NADH and FADH2 and acetyl CoA being produced.
Acetyl CoA enters the TCA cycle and NADH and FADH2 enter the election transport chain
What is the ATP yield from the TCA cycle and electron transport chain?
In the TCA cycle 1 GTP, 3NADH and 1FADH2 are produced
NADH yields 2.5 ATP and FADH2 yields 1.5 ATP
Total yield per acetyl CoA is 10ATP
How is glycolysis regulated?
high levels of citrate and ATP inhibit phosphofructokinase which is an important enzyme in glycolysis
Describe protein metabolism
9 amino acids are essential and must be obtained from the diet
transamination - 1 amino acid is converted to another
oxidative deamination - the amino acid of an amino acid is lost as ammonia, which can enter the urea cycle
Describe energy requirements
Basal energy expenditure (BEE) / basal metabolic rate (BMR) represent the energy required to maintain basic functions when a person is lying down, relaxed, in a normal ambient temperature
What is BMI?
Body mass index
weight/height squared
What are the ranges for BMI?
30 obese
Describe anorexia
self induced weight loss
low body weight
body image distortion
endocrine disorder
Describe the psychological presentations of anorexia
overvalued idea re weight
dysphoria
abnormal behaviours - food fads, odd eating, drink in excess or too little, secretiveness, avoidance of social eating
Describe some compensatory behaviours in anorexia
excess exercise to burn energy
use laxatives, induce vomiting
Describe some of the personality traits involved in anorexia
premorbid perfectionism
introversion
poor peer relationships
low self esteem
“perfect” child becomes angry, deceptive, manipulative, withdrawn
Describe the treatment for anorexia
inpatient / outpatient
psychological intervention
physical monitoring
diet plan
SSRIs when clear obsessional component
Describe bulimia
cravings
binge eating
counteractive behaviour
body image symptoms
physical effects to purging
also malnourished
can be overweight
Describe the management of bulimia
outpatient based
self help resources
CBT - 16-20 sessions
high dose SSRI
periodic biochemistry monitoring
Describe the 2 groups of organs in the alimentary system
digestive tract
accessory organs - salivary glands, gallbladder, liver, pancreas
Describe the structure of the GI system
mucosa
submucosa
muscularis propria
adventitia
What is in the mucosa?
epithelium, lamina propria, mucularis mucosae
What is in the muscularis mucosa?
inner circular, outer longitudinal
Describe the pharynx
muscular tube
conducts air
muscles direct food to oesophagus
3 parts - nasopharynx, oropharynx and larynnopharynx
Describe the oesophagus
muscular tube - pharynx to stomach
lies in neck, thorax and abdomen
posterior to the trachea and heart
pierces diaphragm
sphincters
Describe the stomach
found ion the left hypochondriac / epigastric region
endocrine cells produce gastrin
parietal cells produce HCl and intrinsic factor
chief cells produce pepsinogen
Describe the small intestine
Comprises duodenum, jejunum and ileum
primary site for digestion and absorption
describe the deodenum
receives chyme
short length
contains Brunner’s glands - alkaline secretion
receives common bile duct (sphincter of Oddi)
major duodenal papilla
bile
pancreatic “juice”
Ends a deodenojejunal junction
deserve the pancreas
Dual purpose
exocrine gland - 99%
endocrine gland - islets of Langerhans
What does the exocrine portion of the pancreas produce?
many digestive enzyme
bicarbonate ions
What does the endocrine portion of the pancreas produce?
hormones - insulin, glucagon, somatostatin
Describe the liver
metabolism - storage of glycogen and release of glucose
protein synthesis
inactivation of hormones, drugs
excretion of waste
produces bile
Describe the large intestine
Caecum - appendix
Colon - ascending, transverse, descending, sigmoid
rectum
What is the blood supply to the GI tract?
3 vessels all arising from the abdominal aorta
coeliac trunk
superior mesenteric artery
inferior mesenteric artery
Describe the divisions of the abdomen
Right and left hypochondriac, epigastric
right and left lumbar, umbilical
Right and left iliac, suprapubic
What nervous system influences digestive processes?
enteric
What does the myenteric plexus do?
GI motility
What does the submucous plexus do?
sensing environment in the lumen
regulating GI blood flow
controlling epithelial cell function
Describe the mouth, pharynx and salivary glands
start digestion by physically chewing food and breaking it down with saliva
What are the functions of saliva?
Maintaining healthy oral tissues - contain thiocyanate ions, proteolytic enzymes and antibodies
starts digestion of carbohydrates
contributes to digestion of fats
its absence provides the urge to drink
provides mucous
keeps mouth moist for speech, oral comfort, chewing and swallowing
Describe salivary amylase
produced by acini glands
pH optimum 6.9
activity continues for 15-30 minutes in mouth and stomach
breaks down alpha 1,4 glucosidic bonds
starch, glycogen > maltose, maltotriose and alpha limit dextrins
Describe the functions of the stomach
storage of food
churn and mix with gastric secretions
acid and pepsin secretions
slow emptying of digestive contents into small intestine
What are the gastric secretions?
mucous secreting cells
acid secretion
chief cells produce pepsinogen
intrinsic factor
Why is mucous important in the stomach?
protects stomach from damage by gastric acids
What do acid secretions in the stomach do?
breakdown of connective tissue, activates pepsin, solubilises calcium and iron, acts as a barrier to microbes
What does pepsinogen do?
converted into pepsin, digests proteins
What is intrinsic factor important for?
absorption of vitamin B12
Describe pancreatic juice
made of aqueous and enzymatic component
alkali - contains bicarbonate
buffers acidic secretion of stomach
protects mucosa
enters small intestine
provides right pH for proteolytic enzymes
What are the two types of pancreatic secretions?
proteolytic and non-proteolytic
Give examples of proteolytic enzymes
trypsin
yhromotrypsin
carboxypeptidase
elastase
phospholipase
secreted by acinar cells as zymogens
Give examples of non-proteolytic enzymes
amylase
lipase
ribonuclease
deoxyribonuclease
released in active form
Describe pancreatic amylase
endoamylase, similar to salivary
digests alpha 1-4 glucose bonds
digests starch and glycogen to maltose maltotriose and dextrins
Describe pancreatic lipase
acts of water insoluble triglycerides
releases fatty acids and 2-monoglycerides
Describe liver bile
synthesised in the hepatocyte
stored in the gall bladder
released into duodenum after meal
What is bile composed of?
bile acids
phospholipid
cholesterol
bilirubin
electrolytes
detoxified drugs
What are the functions of bile?
emulsification of fat particles
helps in absorption of fats by forming complexes called micelles
What is the function of the duodenum?
mixing secretions from pancreas, liver and its own with food, neutralising the acid, further digestion, absorption
What is the function of the jejunum?
completing breakdown, nutrient absorption
What is the function of the ileum?
nutrient absorption
What is chylomicron formation?
if a fatty acid has more than 12 carbons, then triglyceride reformed in a cell coated protein, phospholipid and cholesterol enclosed in vesicles
What do the absorptive cells of the small intestine release?
digestive enzymes
What do goblet cells in the small intestine produce?
mucous
What do granular cells in the small intestine produce?
enzymes
what do endocrine cells in the small intestine produce?
hormones
Give examples of brush border enzymes
peptidases
lactase
lucrase
maltase
Describe protein digesition
starts in the stomach - pepsin
continues in small intestine - trypsin, chymotrypsin, carboxypeptidase
continues at brush border amino peptidases
amino acids and peptides absorbed by active transport vis 7 sodium linked carriers
Describe the digestion of fats
pancreatic lipase, collapse
mixed with emulsified fat and bile acid
triglyceride > 2-monoglyceride and fatty acids
Describe fatty acid absorption
at brush border lower pH at mucosa reduces solubility of lipid in micelles
fatty acids are absorbed by micelles
