Module 5 - Topic 2B-3: The Digestive System and Renal System Flashcards
Salivary Glands
secretes saliva
Parotid Glands
salivary glands
either side of mouth, infront of ears
Sublingual glands
under the tongue
Submandibular glands
under the lower jaw bone
Buccal glands
small intrinsic glands scattered throughout mucosa of oral cavity
Saliva
cleanses mouth
dissolves food chemicals
moistens food to aid swallowing
contains salivary amylase that initiates chemical digestion of starch
saliva makeup
IgA antibodies
lysozyme (bacterial enzyme)
defensins (antibiotic proteins)
cyanide compound that prevents growth and infection of harmful bacteris
Pancreas location
near start of small intestine
Pancreas - makeup
contains a mixture of exocrine and endocrine glandular tissue
Exocrine portion of pancreas
contains acini that secrete pancreactic juice into a duct that goes to small intestine
acini
small clusters of secretory cells
Pancreatic juice
contains alkaline bicarbonate- rich mixture, specialised for digestion of proteins, sugars, lipids and nucleic acids
neutralises the acidic chyme entering the small intestine from stomach
Endocrine portion of pancreas
pancreatic islets
islets of Langerhans
secretes hormones directly into bloodstream
Alpha islet cells
secrete glucagon
Beta islet cells
secretes insulin
Delta islet cells
secrete somatostatin
glucagon function
increase blood glucose levels by stimulating glucose release from liver
Insulin function
lower blood glucose levels by enhancing membrane transport of glucose into tissue cells
influences protein and fat metabolism
Insulin function after glucose enters cells
catalyses oxidation of glucose for ATP production
joins glucose molecules together to produce glycogen
converts glucose to fat
Liver
influences main different activities
Liver - main functions
produces bile
metabolises lipids and other nutrients
stores glucose in form of glycogen
Bile
acts as a detergent and assists digestion and absorption of fats
Hepatocytes
liver cells that produce bile
how bile gets to gallbladder
collected from liver by a network of ducts and drains into gallbladder
Gallbladder
small green sac under the right lower surface of the liver
gallbladder function
concentrates and stores bile
cholecystokinin
intestinal hormone that is released when fatty chyme enters the small intestine from stomach
major stimuli for gallbladder contraction
gallstones
crystals of pure cholesterol, formed when high concentrate of cholesterol
bilirubin
main pigment of bile
waste product of heme
jaundice
caused by a build up of bilirubin in the blood
Portal circulatory system - location
begins at capillaries of digestive organs and ends in portal vein
Portal blood
contains substances absorbed by stomach and intestines
passed through the hepatic lobules
Hepatic lobules
where nutrients and toxins are absorbed, excreted or converted
portal hypertension
restriction of outflow through hepatic portal system
liver lobules
tiny functional units in liver
shaped like a hexagonal wheel
liver lobule makeup
central vein with sheets of hepacytes radiating outwards
portal triad
at each point of hexagon
consists of arteriole, venule and bile duct
sinusoids
leaky capillaries that blood from ateriole and venules passes through to get to central vein
kupffer cells
star shaped macrophages that remove debris and worn out blood cells from blood
sheets of hepatocytes in liver lobule - function
process blood borne nutrients
store fat soluble vitamins
detoxify blood
produce bile
bile canaliculi
tiny canals that hepatocytes secrete bile
Hepatitis
inflammation of liver
HVA and HVE
transmitted by food or water contamination
HVB and HVC
carried in infected blood or body fluids
HVD
mutated virus that needs HVB to be infectious
Non viral Hepatitis
result of drug toxicity, pesticide poisoning or wild mushroom poisoning
cirrhosis
progressive chronic inflammation of liver as a result of chronic alcoholism
Urinary system - function
control the amount of water present in body and eliminate water soluble wastes
human urinary system
recycles water and eliminates the need for constant drinking
primary organ of urinary system
kidneys
Kidney function
remove waste products from water and return water to rest of body
act as endocrine glands that secrete erythropoietin and renin
activates Vitamin D to assist bone formation
supply glucose to body during fasting
Urine
contain waste products such as toxic metabolic water substances and salts
major components of urinary system
ureters, urinary bladder and urethra
Functions of urinary system
maintains salt, water and pH balance of blood and removes wastes
renin
helps regulate blood pressure and kidney function
Kidney - location
back of upper abdominal cavity
Kidney - makeup
highly vascularised bean shaped protected by renal fascia, adipose layer and inner renal capsule
has 3 main regions, outer cortex, inner medulla and renal pelvis
renal fascia
outer layer of dense fibrous connective tissue
renal capsule
thin, shiny, transparent membrane on surface of each kidney
Outer cortex of kidney
light coloured
granular appearance
site of filtration
Inner medulla
deep below cortex
dark reddish brown colour
contains renal pyramids
re absorption and secretion
renal pyramids
cone shaped masses in inner medulla of kidney
papilla
apex of renal pyramids
Renal pelvis
central junction that papilla point towards
large funnel shaped collecting tube which is continuous with ureter leaving the kidney
calyces
branching extensions of renal pelvis
collect urine which drains constantly from pyramids and empties into renal pelvis
renal artery
enter each kidney carrying blood to be filtered
Renal vein
leaves kidney, carries blood away
Nephrons
tiny blood filtration units in kidney that carry out the processes of urine formation
Nephron makeup
glomerulus
Bowmans capsule
Renal tubule
Glomerulus
small pin head sized tuft of arterioles
Bowmans capsule
cup like structure that holds glomerulus and allows fluid to pass from the blood into collecting tubules
Renal Corpuscle
glomerulus and bowmans capsule
Renal tubule
tiny collecting tube divided into 3 regions
Proximal convoluted tubule (near twisted)
loop of henle
Distal convoluted tubule (distant twisted)
Fenestrations
small holes in the endothelium of the arterioles in the glomerulus
allow fluid and solutes to leak out of bloodstream
Basement membrane
extracellular matrix of collagen fibres that underlie all epithelia
prevents large solutes from going any further
Podocytes
epithelial cells that filter the fluid that comes through basement membrane
have tiny foot like projections called pedicels
pedicels
foot like projections which press against basement membrane restricting the surface area for filtration and regulates amount of fluid being filtered
fluid that passes pedicels
contains only small molecules like salts
collected into bowmans capsule and carried down renal tubule
Urine formation
involve 3 major processes
glomerular filtration
tubular reabsorption
Tubular secretion
Glomerular filtration
begins in renal corpuscle
passive, non selective process where fluids and solutes are forced through membrane under hydrostatic pressure
Tubular Reabsorption
proximal convoluted tubule reabsorbs glucose, lactate and amino acids back into body
Role of Loop of henle in selective reabsorption
since extracellular space becomes hypertonic , water moves by osmosis out of descending limb into extracellular space
descending limb of loop of Henle
freely permeable to water
impermeable to solutes
Ascending limb of loop of Henle
impermeable to water
cells lining the ascending limb have a pump that transports salt from urine back into extracellular space to the bloodstream
Further processing of filtrate
occurs in distal convoluted tubules and collecting ducts
distal convoluted tubules and collecting ducts - permeability
have hormone dependent permeability to water
Aldosterone
secreted by adrenal glands
targets distal convoluted tubules and collecting ducts and enhances Na+ and water reabsorption into body
reduces potassium ion concentrations in the blood
Antidiuretic Hormone
released by posterior pituitary gland
increases the permeability of collecting ducts
Tubular secretion - location
proximal convoluted tubules
cortical parts of collecting ducts
late regions of distal convoluted tubules
Tubular secretion - function
disposal of unfiltered substances
elimination of undesirable substances or end products
ridding body of excessive potassium
controls blood pH
Ureters
slender tubes that convey urine from kidneys into urinary bladder
renal calculi
kidney stones
block ureter and flow or urine
Hydronephrosis
backflow of urine into kidneys
leads to renal failure
urinary bladder
collapsible smooth muscular sac that temporarily stores urine
interior of bladder
lined with protective mucosa
has openings to ureters and urethra
trigone
smooth triangular region of bladder that has 3 openings
bladder wall makeup
inner mucosa
middle thick smooth muscular layer
outer fibrous connective layer
Urethra
thin muscular tube
drains urine from bladder to outside
internal urethra sphincter
at bladder urethra junction
involuntary control
keeps urethra closed
external urethra sphincter
surrounds urethra and formed from skeletal muscle
voluntary control
voluntary constrictor of of urethra
