BIO288 Sp2024 Final Exam Review Slides PDF

FINAL EXAM REVIEW SLIDES Digestive System Digestion describes: 1. All of the tissues of the physical and chemical processes used to breakdown food 2. The sensory system used to locate the food 3. The physical structures that mechanically disrupt the food 4. The chemical processes that break food int...

FINAL EXAM REVIEW SLIDES Digestive System Digestion describes: 1. All of the tissues of the physical and chemical processes used to breakdown food 2. The sensory system used to locate the food 3. The physical structures that mechanically disrupt the food 4. The chemical processes that break food into forms that can be transported and metabolized into other molecules Anatomy of the Digestive System: 3 main divisions Foregut Develops into: the esophagus, stomach, gallbladder, pancreas, and liver Role: chemical and physical processes Midgut Develops into: the small intestine, much of the large intestine, and appendix Role: Critical in processes of digestion, absorption of nutrients, immune functions, and endocrine system. Hindgut Develops into: last 35% of transverse colon, descending colon, sigmoid colon, rectum, and proximal anus. Role: reabsorbs water and electrolytes and stores fecal matter Review of Digestion 5 Step 1: Ingestion Primary route by which food enters the digestive system Some of the nutrients are degraded to produce chemical energy while the rest is used as building blocks Digestion starts in the mouth (contains intraluminal enzymes: amylase which breaks down carbs and lingual lipase which breaks down lipids)! Chemical Digestion Why do we break down nutrients? Where do we begin to break things down? Step 3: Absorption Structure of the gastrointestinal wall Mucosa Mucous Membrane: a thin layer of epithelial cells of many types including absorptive cells which transport nutrients to blood Lamina Propria: layer of connective tissue containing small blood vessels, nerves, and lymphatic vessels. Muscularis Mucosae: thin layer of smooth muscle cells that make the mucosa fold Structure of the gastrointestinal wall Submucosa Layer of dense connective tissue Contains large blood vessels, lymphatic vessels, and nervous fibers of the Enteric Nervous System (ENS) Muscularis Externa Involved in mechanical processing, motility, and is coordinated by the ENS Serosa Consists of inner layer of fibrous connective tissue which provides structural support Secretes a lubricating fluid facilitating the sliding of organs past each other Motility Gut muscles are arranged in two ways where: o Outer layer contains longitudinal muscles o Inner layer contains circular muscles Types of motility: o Peristalsis: wavelike muscle contractions leading propulsion towards anus o Segmentation: circular muscle contractions leading to mixing and subsequent absorption Enterocytes: sites of absorption Contain intestinal villi which allow for a higher surface area MORE SURFACE AREA = MORE ABSORPTION Nutrients are moved across the apical surface of the intestinal epithelia based on whether they are polar or non-polar: Polar nutrients are transported via secondary active cotransport AND secondary active counter transport Non-polar nutrients (lipophilic) are transported via simple diffusion Liver Urinary System Homeostatic Functions of the Urinary System 1. Regulates blood volume and blood pressure: by adjusting volume of water lost in urine and releasing erythropoietin 2. Regulates plasma ion concentration: such as sodium, potassium, and chloride ions 3. Stabilizes blood pH: by eliminating hydrogen ions and bicarbonate ions in urine 4. Conserves valuable nutrients: by preventing excretion of nutrients 5. Assist liver in detoxifying poisons Anatomy and function of the Urinary system Regulates blood volume and pressure Regulates plasma ion concentration Regulates blood pH Regulates plasma osmolarity and conserves valuable nutrients Assists in detoxification Kidneys- reabsorb water back into the body creating urine. The ureter, bladder and urethra act as transport systems for waste. ○ This is your urinary tract Urination- process of eliminating urine Anatomy of the kidney Renal cortex: Superficial portion of the kidney in contact with renal capsule Renal medulla: center area of the kidney and contains renal pyramids and renal columns Renal lobe: composes the nephron (the functional unit of the renal process) which produces the urine Renal papilla: ducts that discharge urine into minor calyx Major calyx: formed by four or five minor calyces Renal pelvis: large funnel shaped chamber which is connected to the ureter and drains the kidney Hilum: point of entry or renal artery and nerves as well as the point of exit for the renal vein and ureter 4 Major Structures Renal papilar ○ ○ Major Calyx ○ Group of minor calyx that come together to move urine Renal pelvis ○ ○ Cup shaped Leads to minor calyx Large funnel Connected to ureter Hilum ○ ○ Point of entry for renal artery and renal nerves( for connection to the brain) Exit for renal vein and ureter How the urinary system functions? (Nephron functions) Main goal: filter the blood and reabsorb water ○ High blood supply to the kidney through the renal veins and arteries (from the aorta and vena cava) Flow of urine ○ Glomerulus→ tubules→ calyx → pelvis→ ureter ○ Glomerulus Bowman's Capsule ○ Renal tubules Capillary network of blood vessel for filtration (thin) Acts as a cheesecloth→ blood can't come in but only water can absorb most of the water Has podocytes(endothelial cells) that has tight junctions for more filtration Renal tubules ○ ○ Convoluted tubules: Filtered water moves down here Proximal straight tubules Nephron Types: Cortical vs. Juxtamedullary Cortical nephrons: Short loop of Henle Most common (80-85% of nephrons) Juxtamedullary nephrons: Responsible for medullary osmotic gradient Long loop of Henle Renal Function 1. Glomerular filtration* a. 2. Reabsorption* a. b. 3. Take ions, nutrients, vitamins, and water back into the body From tubules to peritubular capillaries Secretion* a. 4. Production of filtrate by moving water, ions, toxins, etc. from glomerular capillaries to glomerular (Bowman’s) capsule Movement of unnecessary ions from peritubular capillaries to tubules Excretion a. Movement of filtrate from tubules out of the body *happen inside nephron Filtration Glomerular Filtration Rate: dependent on four pressures A. B. C. D. Glomerular hydrostatic pressure Capsular hydrostatic pressure Blood osmotic pressure Capsular osmotic pressure What gets through the podocyte pores? What remains in the blood? How does the blood vessel radius impact these pressures? Starling Forces Glomerular capillary hydrostatic pressure (PGC): pressure of blood and fluid pushing against walls of capillary (more volume → higher pressure) 60 mmHg High due to resistance of efferent arterioles Bowman’s capsule oncotic pressure (BC): Similar to osmotic pressure but it describes the pressure formed by plasma proteins which do not move across to the bowman's capsule. 0 mmHg null due to lack of proteins inside the bowman’s capsule Bowman’s capsule hydrostatic pressure (PBC): Fluid pushing on walls inside the bowman’s capsule Will be lower than that of glomerular capillary because of the large area of the bowman’s capsule and the fluid is not being restricted from leaving (volume moving away and going down renal tubules) 15 mmHg due to large volume of filtrate in closed space but not high compared to those found in capillaries Glomerular oncotic pressure (GC): High due to high plasma protein concentration 29 mmHg Net Result Net pressure forces water and some solutes into the Bowman’s capsule NOTE: Blood cells and large proteins CANNOT cross the filtration membrane Glomerular filtration rate DOES NOT VARY with circulatory system blood pressure. Pressure inside the glomerulus is controlled via: Intrinsic control: kidney adjusts constriction and dilation of arterioles Extrinsic control: neural and hormonal adjustment of arteriole Water Balance,Osmosis, and Water Reabsorption Kidneys regulate the concentration of water in the plasma, maintaining a balance between bringing in water and excreting it ○ Water Intake + Metabolically Produced = Water Output + Water Used Balance is maintained largely thanks to the role osmosis plays in reabsorption ○ Water movement favors the more concentrated solution, i.e. whatever direction that will make the two solution concentrations more similar Where is water reabsorption occurring? ○ Proximal tubules: 70% of filtered water is reabsorbed, not regulated ○ Distal tubules and collecting ducts: remaining water reabsorbed, regulated by antidiuretic hormone Nephron loop: made up of the descending and ascending limbs ○ Descending limb: permeable to water and not solutes ○ Ascending limb: permeable to solutes and not water Reabsorption and Secretion Reabsorption: substances that need to be kept in the body Secretion: process to remove substances from the body, separate from filtration Other definitions: Fluid inside the nephron is known as filtrate Medium inside the peritubular capillaries is blood Fluid between the two is in the interstitium Reabsorption: Active, Passive, and Water Regionality of solute and water absorption in the nephron, dependent on the transporters available Active transport necessary for moving solutes against the concentration gradients, but requires energy What is an example of an active transporter? Water absorption requires transporters called aquaporins because water is polar, but will move from low osmotic pressure to high osmotic pressure Passive transport moves solutes from high to low concentration Creation of the Osmotic Gradient Ion movement in the ascending limb of the loop of Henle produces a gradient between the interstitial space and tubular space This allows water to be passively transported from the descending limb This gradient allows the juxtamedullary nephrons to absorb as much water as possible What solute is used to help maintain this gradient? Hint: It’s produced by the liver Hormonal Regulation of Urinary System Anti-diuretic hormone (vasopressin): accounts for 20% water reabsorption in the distal tubule and 10% in the collecting ducts ADH signals the insertion of aquaporin-2 in the collecting duct cells If dehydrated: ↑ ADH → ↑ Aquaporin-2 → ↑ Water reabsorption If hydrated: ↓ ADH → ❌Aquaporin-2 → ↓ Water reabsorption Hormonal Regulation of Urinary System Diuretics: Caffeine Inhibits Na+ Reabsorption Coffee contains caffeine Caffeine inhibits sodium reabsorption in the renal tubules Increases solute excretion and water excretion (water follows solutes) Diuresis → increase/excessive production of urine (caffeine) Diuretics: Alcohol Prevents the Product of ADH ADH synthesized in the pituitary gland The more alcohol you consume, the less ADH produce, the more water you lose Ultimately, causes dehydration (next day = hangovers) Regulation of Blood Pressure Stop and Think! Question: In chemical digestion, which enzyme is responsible for breaking down proteins into smaller peptides? Stop and Think: Imagine there is a mutation that renders the body unable to produce pepsin. How might this mutation affect the process of protein digestion? Stop and Think! Question: In chemical digestion, which enzyme is responsible for breaking down proteins into smaller peptides? Answer: The enzyme responsible for breaking down proteins into smaller peptides is called pepsin. Stop and Think: Imagine there is a mutation that renders the body unable to produce pepsin. How might this mutation affect the process of protein digestion? Answer: Without the production of pepsin, the process of protein digestion would be significantly impaired. Proteins would not be broken down into smaller peptides, making it difficult for the body to absorb the necessary amino acids for various cellular functions. This could lead to malnutrition, inadequate muscle growth and repair, and other complications related to protein deficiency.