9 - Renal and Digestive Systems

colon

organ that filters out solid waste by reabsorbing water from it → makes feces

liver

organ that filters hydrophilic materials; things that have been absorbed by blood, but too hydrophilic to be absorbed by plasma

kidney

organ that takes plasma out of blood → push it in kidney tubules → modify/filter it

cannot. it can only eliminate hydrophilic waste, such as things eaten, absorbed by blood and dissolved in plasma

if waste products are insoluble in the bloodstream, can it be filtered out by kidney?

1. regulates BP, ion/water balance, pH

2. secretes erythropoietin (EPO) to increase RBC production

3. activates vitamin D

4. gluconeogenesis (a little bit)

what are some other kidney functions, apart from filtering blood plasma? (4)

erythropoietin (EPO)

a glycoprotein hormone, naturally produced by the peritubular cells of the kidney, that stimulates red blood cell production

1. colon

2. liver

3. kidney

what are the excretory organs? (3)

internal urinary sphincter

structure that sits between the bladder and urethra, made out of smooth muscle (involuntary contraction)

contracts as the bladder fills, relax when bladder empties

external urinary sphincter

structure at the distal urethra, made out of skeletal muscle (voluntary contraction)

relaxes as you pee (you control); normally it stays contracted

contracts, contracts

as the bladder fills, the internal urinary sphincter ___________ (contracts/relaxes) and the external urinary sphincter ___________ (contracts/relaxes).

contraction

voiding urine (not wanting to pee despite needing to) begins with voluntary ______________ (contraction/relaxation) of the external urinary sphincter

contracts, relaxes

when urinating, the external urinary sphincter _________ (contracts/relaxes) to let urine exit. the internal urinary sphincter ____________ (contracts/relaxes) to empty the bladder

nephron

functional part of the kidney between the cortex and the medulla (where all plasma filtration occurs)

1. filtration

2. reabsorption

3. secretion

what are the 3 processes to which the nephron produces urine?

filtration

the act of the kidney moving a substance (blood plasma) across the membrane (capillary wall) using pressure (BP)

reabsorption

the act of the kidney moving a substrate from blood → filtrate → back to blood (urine to blood again)

glucose, amino acids, water, Na+, HCO3-

what substances are usually reabsorbed by the kidney, given normal conditions?

secretion

the act of the kidneys moving substance away from blood to filtrate (blood → urine) d

drugs, wastes, creatinine, H+, and K+

what substances are usually secreted by the kidneys?

glomerulus

structure in the kidney that contains the capillaries to push plasma out of the bloodstream + does filtration via arterioles

contains afferent and efferent arterioles

dilate afferent arterioles (let blood in nephron) and constrict efferent arterioles (let blood out)

how to increase GFR (glomerular filtration rate by modifying afferent and efferent arteriole? (should they be constricted/dilated?

proximal convoluted tubule

kidney structure where most reabsorption (Na+, glucose, water) and secretion (H+, K+, creatinine, waste) occurs

microvilli. it’s not regulated babes <3

what does the proximal convoluted tubule reabsorb materials with? how is this regulated?

loop of henle

kidney structure that sets up a concentration gradient in the medulla so that the deeper portions of medulla is increasingly salty (increasing osmolarity)

ascending loop of henle

kidney structure that’s impermeable to water, but permeable to salt (Na+ leaves (active transport) but water can’t follow)

descending loop of Henle

kidney structure that is permeable to water, but impermeable to salt

1. filtrate entering nephron loop is isosmotic to both blood, plasma, and cortical interstitial fluid

2. water leaves in descending LoH down its osmotic gradient (this concentrates the filtrate)

3. filtrate reaches the highest concentration at the bend of the loop of henle

4. Na+ and Cl- are pumped out of the filtrate at ascending LoH → increases the interstitial fluid osmolality

5. filtrate is at its most dilute as it leaves the nephron loop.

what are the steps of filtrate traveling through the kidney loop of henle?

distal convoluted tubule

kidney structure that’s a specialized reabsorption/secretion center (where aldosterone (Na+ retention), PTH (Ca2+ retention), and calcitonin (Ca2+ secretion) have effects

more selective than its proximal counterpart

collecting duct

kidney structure that picks up water from many different nephrons to perform regulated water reabsorption

has variable permeability to water based on the presence of ADH (water reabsorption)

antidiuretic hormone (ADH)

hormone that allow water to move OUT of the collecting tube to surrounding areas (water is kept)

there woul be no water permeability → water stays in the collecting duct and gets peed out

what happens if there is no antidiuretic hormone (ADH)?

alcohol and coffee. individual pees more because there is no water retention in kidneys

what substances suppress ADH? what happens if that occurs?

hypotension and dehydration. the kidneys retain fluid by reabsorbing water

what conditions/substances activates ADH? what happens if that occurs?

high, high

when urine volume is low, blood volume is _______ (high/low), and blood concentration is ______ (high/low)

low

when urine volume is high, urine concentration is _____ (high/low)

high

when blood volume is low, blood concentration is ______ (high/low)

remember

1. urine and blood = opposite

2. volume and osmolarity = opposite

remember

1. urine and blood = opposite

2. volume and osmolarity = opposite

1. systemic vasoconstriction

2. sodium and potassium reabsorption

3. ADH secretion (water reabsorption)

4. increase blood volume and BP

what does aldosterone do?

B.

that’s ADH function

which of these is not a function of aldosterone?

A. vasoconstriction

B. water retention

C. Na+ retention

D. increase blood osmolarity

juxtaglomerular apparatus (JGA)

the contact point between the afferent arteriole and distal convoluted tube

baroreceptors (monitor blood pressure)

JGA cells on the afferent arteriole side act as ______________

JGA cells release renin

what does JGA cells do in cases of hypotension?

angiotensinogen → angiotensin I (by renin) → angiotensin II (by ACE) → aldosterone → systemic vasoconstriction

describe the RAAS system, starting with angiotensinogen and ending with aldosterone

kidney. converts angiotensinogen to angiotensin I in the kidney

where is the enzyme renin secreted from? what is its function?

lungs (endothelial cells). converts angiotensin I to angiotensin II

where is the enzyme ACE released from and what is its function?

chemoreceptors (monitor filtrate osmolarity)

JGA cells on distal convoluted tube act as ______________

1. stimulate afferent arteriole to release renin

2. directly dilate the afferent arteriole → increase GFR → more blood in kidney

what do JGA cells on distal convoluted tube do when filtrate osmolarity decrease?

atrial natriuretic peptide (ANP/ANF)

peptide that inhibits renin and aldosterone → vasodilation, decrease Na+ reabsorption → less osmolarity and blood volume → BP lowers

high BP → atria stretch → R atrium releases ANP → vasodilation, inhibition of renin, inhibition of aldosterone

what is the process of high blood pressure regulation in the body?

CO₂ + H₂O ⇆ H₂CO₃ + H+ + HCO₃-

1. HCO₃- = blood reabsorbed

2. H+ are secreted (urine - pH of 6)

what is the chemical formula for kidney pH regulation?

CO₂ + H₂O ⇆ H₂CO₃ + H+ + HCO₃-

[HCO₃-] reabsorption increase, [H+] secretion increase

what happens to the renal pH regulation chemical formula when blood pH is too low (acidic)?

CO₂ + H₂O ⇆ H₂CO₃ + H+ + HCO₃-

[HCO₃-] reabsorption decrease, [H+] secretion decrease

what happens to the renal pH regulation chemical formula when blood pH is too high (basic)?

accessory organs

digestive organs with a role, but it’s not part of the alimentary canal

1. gallbladder

2. liver

3. pancreas

4. salivary glands

name the digestive accessory organs (4)

alimentary canal

muscular tube that goes from the mouth to anus

liver

responsible for:

1. glucose metabolism (gluconeogenesis, glycolysis, glycogen storage, glycogenolysis)

2. makes bile

3. protein regulation (ketogenesis)

4. toxin breakdown

5. makes blood clotting protein

6. lipid metabolism (beta oxidation)

7. triglyceride synthesis and storage (lipogenesis)

bile

amphipathic molecule that emulsifies fat for easier breakdown (does NOT directly breakdown fat)

gallbladder

digestive organ that concentrates and stores bile

pancreas

digestive organ with endocrine and exocrine role (makes insulin and glucagon)

also makes proteases, lipases, amylases, nucleases (breakdown nucleic acids)

synthesize:

1. protease

2. lipase

3. amylase

4. nuclease (breakdown nucleic acids)

saliva is NOT the only thing producing amylase!!!!

what are the exocrine functions of the pancreas?

reminder: exocrine means glands that secrete substances through ducts directly (does not secrete into bloodstream)

secretes:

1. insulin (high glucose)

2. glucagon (low glucose)

what are the endocrine functions of pancreas?

reminder: endocrine = secrete into bloodstream

1. endocrine functions (secretes insulin and glucagon)

2. exocrine functions (synthesize proteases, lipases, amylases, nucleases)

3. dumps bicarbonate onto things exiting stomach → intestines to neutralize the acidic environment of stomach

what are the 3 functions of the pancreas?

dumps bicarbonate onto things exiting stomach → intestines to neutralize the acidic environment of stomach

why does the pancreas secrete bicarbonate into things exiting the stomach?

1. lysozyme

2. amylase

3. lingual lipase

what are the exocrine enzymes secreted by the mouth/saliva?

lysozyme

enzyme that kills bacteria

amylase

enzyme that digests starch

lingual lipase

enzyme that digests fat

esophagus

muscular tube that brings food into stomach (starts as skeletal muscle, then become smooth muscle)

cardiac sphincter

located at the bottom of the esophagus to prevent reflux of stomach contents

pyloric sphincter

located in the stomach and controls the entry of food into the small intestine

stomach

digestive organ that has very little digestion, absorption. acts as a storage tank for food and secretes acids

gastric glands

located in the stomach, has mucus, parietal cells, and chief cells

parietal cells

in the gastric glands of the stomach and responsible for HCl secretion

chief cells

in the gastric glands of the stomach and responsible for pepsinogen secretion (protease that breakdown pepsin)

pepsinogen

protease that breakdown pepsin in the stomach

1. parietal cells (secrete HCl)

2. chief cells (secrete pepsinogen)

what are the exocrine functions of the stomach

1. G cells (secrete gastrin)

what are the endocrine functions of the stomach?

G cells

located in the stomach and responsible for gastrin secretion (activates gastric glands to secrete gastric acid)

gastrin

hormone produced by G cells in the stomach responsible for regulation of the secretion of gastric acid

1. duodenum

2. jejunum

3. ileum

what are the 3 portions of the small intestine

small intestine

digestive organ where ALL digestive and reabsorption occurs

has a huge surface area due to villi and microvilli folds (plicae = the folds)

plicae

the folds of villi and microvilli in the intestine

1. enterokinase making enteropeptidase (cleaves off part of trypsinogen → activate trypsin → chain rxn of enzyme activation

2. brush border enzymes (disaccharidases and dipeptidases are activated)

what are the exocrine functions of the small intestine?

enteropeptidase

enzyme made by enterokinase to cleave off part of trypsinogen → activates trypsin → sets off chain reaction of enzyme activation

brush border enzymes

include disaccharidases and dipeptidases

disaccharidases

enzymes that split disaccharides into 2 monomers for adsorption in the small intestine

dipeptidases

enzyme that splits dipeptides into 2 monomers for adsorption in the small intestine

adsorption

process by which molecules or particles from a gas, liquid, or dissolved solid adhere to a surface.

it is different from absorption (penetration of one substance into the bulk of another)

1. enterogastrone (reduce stomach motility and emptying)

2. CCK (increase bile/pancreatic enzyme release

3. secretin (increase bicarbonate release from pancreas

what are the endocrine functions in the small intestine?

CCK

peptide hormone produced by cells lining the duodenum and jejunum to increase bile/pancreatic enzyme release

triggered by fats and proteins in the intestines

presence of fats and proteins in the intestine

what triggers CCK release in small intestine?

secretin

peptide hormone made by S cells in duodenum to increase bicarbonate release from pancreas

it’s triggered by low pH in the intestine

low pH in the intestine

what triggers the secretin secretion in the small intestine?

large intestine

digestive organ where no digestion/absorption occurs, but water reabsorption and feces storage happen

gives immunity, vision, reproduction, growth, and development

vitamin A function

infections, maternal mortality, blindness

what happens if vitamin A is missing from diet?

help body absorb and retain calcium

vitamin D function

loss in bone density → osteroporosis and fractures

what happens if vitamin D is missing from the body?

helps with blood clotting

vitamin K function

uncontrolled bleeding, osteroporosis, risk of CVD

What happens if vitamin K is missing from the body?