Digestive System Lecture Exam 4 PDF

DIGESTIVE SYSTEM: 7 functions of the digestive system Mechanical processing = to break something apart using physical force (chewing–masticate food) Digestion = using enzymes to chemically break something apart Secretion = to release substances (e.g acids, enzymes, buffers) Abso...

DIGESTIVE SYSTEM: 7 functions of the digestive system Mechanical processing = to break something apart using physical force (chewing–masticate food) Digestion = using enzymes to chemically break something apart Secretion = to release substances (e.g acids, enzymes, buffers) Absorption = to bring substance into the body Excretion = eliminates wastes from the body– excretion of urine, excretion of feces Compaction = dehydrate and form feces Overview- organs are subdivided into: Accessory organs: exocrine glands which help w/ movement, digestion, & processing of food! Salivary glands Liver Gallbladder Pancreas Gastrointestinal (GI) tract | Alimentary Canal: very long canal ≈ 20 ft. long & majority of it is contained within the abdominal p velvic cavity Mouth Pharynx Esophagus Stomach Small Intestine ≈ 18 ft. long Large Intestine Rectum Anus 4 Layers of the Digestive System Innermost layer: MUCOSA = a mucus membrane that lines the lumen - Secretes mucus (lubricates & protects) - Lined w/ mucosal, non keratinized, epithelial tissue (stratified squamous) for protection This mucus membrane layer is being replaced about every 7 days because endures lots of friction ○ In the middle/bottom of digestive tract (e.g stomach, intestines, has more simple columnar epithelium to help w/ secretion of digestive enzymes into GI tract) Helps absorb nutrients in GI tract Specialized secretory exocrine cells ○ Hydrochloric acid ○ Digestive enzymes (into intestines) Enteroendocrine cells → secrete hormones into cardiovascular system to help regulate body Lamina Propia = basement membrane connected to areolar CT ❖ Allow body to have blood vessels, lymphatic vessels, glands, & space Mucosa-associated lymphatic tissue (MALT) ❖ Patrol GI tract and make sure pathogens don't make it into your body Second layer: SUBMUCOSA = areolar connective tissue  - Contains blood vessels, lymph vessels, & nerves - Binds the mucosa layer to the muscularis - Contains specialized neurons known as the plexus of Meissner’s - Help regulate/control the rate of secretion of all glands into lumen Third layer: MUSCULARIS = two layers of smooth muscle (one circular & one longitudinal) - Peristalsis = undulating movements; help GI tract move things through ❖ Circular muscle ❖ Skeletal muscle: control voluntarily Mouth Pharynx Superior half of esophagus Anal sphincter, external anal sphincter ❖ Smooth muscle: non voluntary Typically, the GI tract has 2 layers: there are more nerves called Myenteric plexus/plexus of Auerbach to regulate rate of movement Inner layer: cell fibers run circularly around tube Outer layer: cell fibers run longitudinally In stomach, there is a third layer Superficial (outside) layer: SEROSA = serous membrane — + simple squamous epithelial tissue - Secretes a fluid to lubricate the outside of the GI tract in abdominal cavity & to make sure organs to not get stuck in one another - *** Adventia in pharynx, esophagus, and rectum to help anchor it in the correct location so they have NO simple squamous epithelium Muscularis layer : movement of materials through the digestive system 1. Segmentation : churn (mix), used to mechanically break apart food – digesting material a. The circular & longitudinal section of muscles are contracted in a localized area, they do not move in a particular direction– to squish food back and forth b. Used in intestines 2. Peristalsis : movement, propel the food through – movement of contents a. Used throughout digestive tract (esophagus, small & large intestines) b. Circular layers of smooth muscle contract behind food c. Longitudinal layers will contract in front of food Peritoneum = largest serous membrane in body: made up of areolar CT + simple squamous epithelium Two continuous layers (parietal & visceral) ○ Parietal layer ○ Visceral layer Peritoneal cavity = space in between the two layers of the peritoneum Secretes serous fluid (more 7 liters a day!) and gets reabsorbed back into cardiovascular system Abdominal cavity is exposed to a lot of movement– you want to make sure organs are properly lubricated so they do not potentially rupture—- This membrane folds around most of the organs in the abdominopelvic cavity ★ Important to help: ○ Stabilize organs ○ Pathway for blood vessels and lymphatic vessels to get into organs Has lots of lymph nodes  ★ Retroperitoneal space is largest in the back and extends from the diaphragm to the pelvic brim & contains organs ○ Describes organs that are not surrounded by the peritoneal membrane but is behind it! Kidneys Pancreas Parts of large & small intestines (like sigmoid colon) ★ Mesenteries = folds of peritoneum ○ Provides structural support ○ Hold lymph nodes ○ Passageways for blood vessels & nerves 1. Greater omentum (fatty apron) a. Largest fold b. Lots of adipose tissue c. Lots of lymph nodes for making sure you have proper immune response for anything traveling into body 2. Falciform ligament – attaches liver & anterior abdominal wall a. Not a true ligament! 3. Lesser omentum (under liver) a. Connects stomach, liver, and duodenum b. Contains hepatic artery & hepatic portal vein c. Has common bile duct 4. Mesentery (proper) behind small intestines a. Holds jejunum & ilium to the posterior abdominal wall b. Stabilizes small intestines 5. Mesocolon behind transverse colon a. Holds large intestine to posterior abdominal wall (2 folds) Peritonitis = when the peritoneum, the tissue lining the abdomen, becomes inflamed or infected - Can happen when an organ ruptures & leaks feces Oral Cavity, Esophagus, Deglutition Oral Cavity (Buccal Cavity): Cheeks = lateral walls of oral cavity Labia (lips) = inferior & superior Oral Vestibule = space between labia & teeth – inferior & superior Palate separates nasal & oral cavities + allows you to breathe while chewing ○ Soft palate = muscle & mucus membrane ○ Hard palate = maxilla & palatine bones covered w/ mucus membrane Uvula - prevents liquids/foods from going up nasal cavity & closes nasopharynx Tonsils = lymphatic tissue in oral cavity and pharynx Fauces = opening to oropharynx Salivary glands ○ Secrete & swallow 1-1.5 liters of saliva per day Contains water, ions, buffers, digestive enzymes (ex: salivary amylase), antibacterial enzymes (lysozyme) at low levels  ○ Lubricates, breaks down foreign material, removes waste ○ 3 PAIRS Parotid gland : triggered when you eat super sour/sweet foods Sublingual gland : Submandibular gland : ○ Can be infected - mumps Tongue : skeletal muscle ○ Has mucus membranes Secretes lingual lipase (digestive enzyme that breaks down fats) Anchored to three bones Hyoid Styloid process of temporal bone Mandible Taste buds (receptors Teeth ○ Held in alveolar processes ○ Gingivae = gums that cover alveolar processes ○ Periodontal ligament = holds each tooth in place ○ TOOTH: Crown - superior part Neck - between root and crown Root - (not visible) LAYERS Enamel covers crown : protects tooth from wear & tear, very strong Dentin (in root is called Cementum; anchors tooth to periodontal ligament) Pulp cavity ○ Contains pulp filled w/ connective tissues Has blood vessels, nerve endings, lymphatic vessels Dental arcades (types of teeth) Incisors = cut food Canines = single cusps (cup shape) for tearing Premolars = two cusps for grinding Molars = four to five cusps for grinding Sets of teeth (DENTITIONS) Deciduous teeth “primary” baby teeth ○ 6 months - 12 years old ○ 20 teeth Permanent teeth “secondary” ○ 32 teeth Teeth: Periodontal disease = inflammation and decay of gingivae Bacterial infection ○ Poor dental hygiene ○ Smoking Can be passed between people Pharynx & Esophagus Pharynx is used by both the respiratory & digestive system ○ Lined w/ skeletal muscle (for swallowing)\ ○ 7 openings  Oral cavity 2 eustachian tubes 2 nasal cavities Glottis Esophagus Esophagus = passageway to stomach ○ No digestion ○ Mucosa is stratified squamous epithelium ○ Passes through diaphragm (esophageal hiatus) ○ Has two sphincters Upper esophageal sphincter: when you bring food through it Lower esophageal sphincter: controls when you bring food from esophagus to stomach Deglutition (swallowing) 1. Voluntary Phase : the tongue pushes food bolus toward the pharynx – esophagus is closed off 2. Pharyngeal Stage : Soft palate and uvula move upward to close off nasopharynx a. Muscles contract, forcing the bolus toward the esophagus b. Epiglottis closes the opening to the larynx c. Upper esophageal sphincter relaxes, food is pushed into esophagus 3. Esophageal Stage (peristalsis) a. Slide bolus of food down stomach b. Lower esophageal sphincter opens STOMACH Stomach = capable of storing a lot of food; it is highly expandable & stretchable Mixes food w/ stomach acids and enzymes Does some absorption on water and alcohol Part of the endocrine system : releases important hormone called gastrin into your bloodstream which helps tell body when you are full Parts: ○ Cardia = area where esophagus enters ○ Fundus = storage ○ Body ○ Pyloric Region Pyloric antrum = entrance way Pyloric canal = tube Pylorus = contains ring of smooth muscle called pyloric sphincter ○ Folds – rugae = allow an increase in surface area so you can digest more food by releasing more enzymes & gastric juices Also allows stomach to stretch and expand to accommodate more food Histology: ○ MUCOSA Gastric pits (openings) Gastric glands (tube deeper to the pits) lined w/ cells that provide functions Mucous cell (goblet cell) ○ Secrete mucus into stomach as protective feature Parietal cells ○ Intrinsic factor - special exocrine hormone that helps absorb vitamin B12  ○ Hydrochloric acid Chief cells– enzymes ○ Pepsinogen = breaks down proteins ○ Gastric lipase = breaks down fats Enteroendocrine cells (G cells) = secretes gastrin hormones backwards into bloodstream – so body gets full ○ SUBMUCOSA ☆ ○ MUSCULARIS = has 3 layers of muscle Oblique (inner) Circular Longitudinal layer ○ SEROSA ☆ Stomach performs both mechanical + chemical digestion Mechanical digestion = churns food by using all three layers of muscle by moving food back and forth within the stomach– propulsion and retropulsion Chyme = liquid mixture of partially digested food and enzymes → leaves through pyloric sphincter ACCESSORY GLANDS : Liver, Gallbladder, and Pancreas Liver ○ Recycles old RBCS ○ Lots of macrophages in there to engulf bacteria ○ Activates vitamin D (cholesterol is moved to liver to convert activated cholesterol to vitamin D to help intestines absorb calcium) ○ Metabolism : stores and breaks down carbohydrates, lipids, and proteins ○ Detoxifies drugs & remove old hormones from cardiovascular system & steroids ○ Produces bile!!! Emulsifies (mix) lipids for digestion ; If bile flow is interrupted, the ability to digest and absorb fats and fat-soluble vitamins in the small intestine would be greatly reduced Excrete wastes Gallbladder = stores bile (acts like backup storage when liver produces a lot of bile) ○ 3 parts Neck Body Fundus (storage sack) ○ Bile connects to cystic duct which allows it to take any of the leftover bile from the liver and store it when you are not digesting ○ Hepatic pancreatic sphincter is closed off when there is no food going through small intestine→ pushes bile back to store Gallstones = extra crystals of cholesterol or bilirubin in gallbladder + block cystic duct ○ Cholesterol gallstone= yellow ○ Bilirubin gallstone= black BILE DUCT SYSTEM - hepatic ducts carry bile from liver 1. Bile flows into the right and left hepatic ducts, which carry bile from each side of the liver. These ducts merge to form the common hepatic duct 2. Cystic duct (gallbladder) + common hepatic duct merge to common bile duct 3. Merges w/ pancreatic duct to form HEPATOPANCREATIC AMPULLA to put bile in small intestines at the site Liver blood supply: large blood supply Inferior vena cava– Hepatic portal vein: delivers nutrient-rich blood from aorta Hepatic vein: takes blood back to the inferior vena cava Hepatic artery: supplies oxygenated, nutrient-rich blood from digestive tract to the liver – comes off from abdominal aorta from the celiac trunk Liver Histology: how bile is produced Hepatocytes: Have endocrine functions: can make hormones Have metabolic functions: process and store carbohydrates, lipids, & proteins Produce bile ○ Bile canaliculi → take bile from hepatocytes → canaliculi merge to form bile ductule → empty bile to bile ducts → merge to larger & larger ducts until → bile ducts Blood goes through hepatic sinusoids (channels) through the branches of the hepatic vein & artery: takes in plasma, removes wastes, produce important bile salts (to emulsify lipids); anything they don't use will go back to hepatic sinusoids & leave through central vein & leave through vena cava What is in bile? Lots of water Bile salts– emulsifies lipids for intestines Bile pigments– leftovers from breaking down RBC, wastes Pancreas (behind stomach) ○ Retroperitoneum - behind stomach + duodenum Head, body, and tail ○ Accessory duct - leads to duodenum Minor duodenal papilla → opening for accessory duct to small intestine ○ Pancreatic duct (main) - leads to duodenum Leads to hepatopancreatic ampulla → opening duodenal papilla Opening is regulated by the hepatopancreatic sphincter which regulates when the juices from the pancreas + bile duct are allowed to go into small intestine Pancreatic acini cells (exocrine cells) Create pancreatic juice ○ Buffers to neutralize stomach acid so it does not damage the rest of the digestive system ○ Digestive enzymes in juice to digest proteins in food Pancreatic amylase, trypsin, chymotrypsin, etc. Pancreatic lipase to digest fats + carbs Ribonucleases and deoxyribonucleases — help digest amino acids from food ○ Secretes into small intestine Why we need the pancreas: severely impact digestion The body may not digest food properly due to the lack of essential digestive enzymes produced by the pancreas & lead to malnutrition The absence of bicarbonate, which neutralizes stomach acid in the intestines, could cause irritation and damage to the intestinal lining. INTESTINES small intestine : Performs 90% of the digestion and absorption of food About 10 feet in adults, can be about 20 in a cadaver because of relaxed muscularis 3 sections ○ Duodenum = 1 foot is retroperitoneum Major + minor duodenal ampulla- openings for pancreatic juices and bile ○ Jejunum = 3 feet ○ Ileum = 6 feet Ileocecal sphincter (valve) Use both mechanical & chemical ○ Segmentation & peristalsis to break apart food ○ Digestive enzymes that chemically break apart food; by pancreas & epithelial cells Histology: MUCOSA Simple columnar epithelium ○ Goblet cells: secrete mucus Villi : Lamina Propia = basement membrane connected to areolar CT; GOES UP & DOWN ❖ Each villi has its own set of capillary beds & lymphatic capillaries, lacteal (specialized)! SUBMUCOSA ☆ MUSCULARIS = has 2 layers of muscle SEROSA ☆ Increase surface area: maximize nutrient absorption - Circular folds that cause chyme to bump, swirl, and spiral through small intestines - Villi = projections of mucosa - Microvilli = projections of cell membranes Celiac disease: where villi get damaged and turned into scar tissue– from gluten; results in bloating and chronic diarrhea because of not digesting food Large intestine : Where chyme goes from liquid to solid Bacteria in large intestines digest whatever is leftover + turn into nutrients ○ Vitamin K and B vitamins are created by bacteria 4 parts ○ Cecum: contains ileocecal sphincter + appendix Appendix houses intestinal bacteria; can get clogged w/ chyme ○ Colon : Ascending colon Transverse colon Descending colon S shaped — sigmoid colon ○ The two layers of smooth muscle do not surround entire colon, thus why we have bumps Haustra = pouch Teniae coli = band that runs along colon  ○ Openings of intestinal glands → absorptive cells which help absorb water Goblet cells ○ RECTUM about 6 inches ○ Anal Canal: has sphincters to allow you to control when you defecate Internal canal sphincter: smooth muscle; feces stretch Nervous tissue → triggers release reflex External anal sphincter: skeletal muscle Can use abdominal muscle to push internal organs and apply pressure to push feces out Anal canal Diarrhea = food going through intestines too fast Constipation = rate of movement in intestines are too slow ○ Delayed defecation ○ Lacking in fiber Fibers give feces bulk and help move along ○ Dehydration Intestinal Microbiota ○ Most bacteria in body are healthy Only a few cause disease ○ Antibiotics can kill most bacteria in body Less effective Allows harmful bacteria to take over Clostridium difficile (C.diff) ○ Deadly infection ○ Constant bloody diarrhea for months Fecal transplant = transplant healthy bacteria Normal bowel movement : 3 times a day → 3 times a week ○ Health ○ Age ○ Diet ○ Exercise Colorectal cancer ○ One of the deadliest cancers in men and women Poor diet, genetic risk factor, alcohol, HPV DIGESTIVE SYSTEM Try answering this question using your current knowledge - in your honor don't peek at your notes/book! (Don't worry, you will earn full credit even if you aren't correct, the point of this is to try.) Using your current knowledge, write a few words to help explain each of these digestive terms: Mechanical processing Digestion Secretion Absorption Excretion Compaction During mechanical processing of chewing, we are using our teeth to physically break down food into smaller pieces so it can be more easily swallowed to later be digested. Digestion is the process of breaking down food so it can be used by our body or exits our body as waste. Secretion in digestion is a process where specialized cells are secreting saliva/fluids containing substances that will help break down food. Absorption in digestion is the process of taking in nutrients from the food we eat so our body can use it. Excretion is the process of removing excess waste that is not being used by our body. Compaction is the process of turning excess waste (indigested food) into feces so our body can remove it. #2 Check all that apply Muscle tissue is found in which layer of the digestive tract? Muscularis #3 Match each of the mesenteries with the appropriate description: Vocabulary word bank: Greater omentum, Lesser omentum, Falciform ligament, Mesentery proper, Mesocolon Connects the anterior surface of the liver to the anterior abdominal wall : falciform ligament Connects the ileum and jejunum to the posterior abdominal wall : mesentery proper Connects the large intestine to the abdominal wall : mesocolon Has the most fat, largest of the mesenteries : greater omentum Runs between the lesser curvature of the stomach to the fissure of the liver : lesser omentum #4 If you laugh so hard that milk comes out your nose, what did you fail to do? You did not raise the soft palate and uvula #5 Check all that apply If your pancreas stopped functioning, how would it affect your digestive system? Your stomach acid may damage your intestines You may not digest your food #6 If the flow of bile was interrupted (either through a gallstone or a blockage), how would this affect the ability to digest or absorb chyme in the small intestine? You wouldn’t be able to digest fats #7 What are the steps in the defecation reflex? Then what needs to happen in order to defecate? The defecation reflex begins with the movement of chyme (liquid mixture of partially digested food and enzymes) moves past the small intestines and into the large intestine where the large intestine has absorptive (goblet) cells which help absorb water, turning chyme from liquid to solid. As wastes move into the rectum, the defecation reflex occurs. The feces activates sensory receptors in the stretched rectum and stimulates the internal anal sphincter and allows feces to move toward the anal canal. For us to defecate, we must consciously decide to relax the external sphincter (skeletal muscle) and also can use abdominal muscles to push internal organs and apply pressure to push feces out. #8 Diarrhea and constipation are both highly dangerous in elderly patients and often lead to death. Why? Diarrhea and constipation are both highly dangerous in elderly patients and often lead to death due to many factors: risk of dehydration, electrolyte imbalances, and infections. When patients have diarrhea, that means the food is going through the intestines too fast and nutrients are not being absorbed properly. This can lead to rapid fluid loss and severe dehydration and electrolyte imbalance. This can result in other complications because we need them to regulate body organs for function. As for constipation, it happens when the movement of food in the intestines is too slow. When the intestines slow down too much, it may cause build up of stool and may become life-threatening because the build up may lead to infection or rupture. URINARY SYSTEM has a large effect on the cardiovascular system! 1. filters blood 2. removes excess water & solutes 3. allows us to store urine that is produced 4. allows us to voluntarily urinate Regulation of blood pressure: the urinary system regulates blood pressure by: controlling the volume of blood and the balance of sodium and water When blood pressure is high, the kidneys filter excess sodium and water, helping to reduce the volume of blood and lower pressure Regulation of blood pH: kidneys selectively remove hydrogen ions & reabsorb bicarbonate ions in blood → urinated out Regulating glucose: lower or raise blood glucose level ; gluconeogenesis Regulating blood ions content: Na+, K+, Ca2+, Cl- Kidneys produce endocrine hormones Excretes wastes out of blood: ammonia, urea, creatine Organs: KIDNEY (2) URETERS (2) URINARY BLADDER (1) URETHRA (1) KIDNEY: external anatomy ❖ Sit retroperitoneally = sit behind peritoneum, the serous membrane that lines abdominopelvic cavity ❖ Has red color due to lots of blood supply ❖ Renal = of the kidney Tissue Layers Surrounding Kidney 1. Renal capsule (fibrous capsule) : contains kidney shape  2. Adipose capsule (perinephric fat capsule) = padding 3. Renal fascia = attaches the kidney to the abdominal wall KIDNEY: Internal anatomy Cortex: outer layer of an organ - Contains renal corpuscle - Distal and proximal convoluted tubules - Proximal ends of collecting ducts Medulla: middle of an organ - Nephron loops - Distal ends of collecting ducts Contains: Fibrous (renal) capsule Renal column Renal pyramid Renal lobe ○ Nephron = functional units of kidney Filters blood to make urine; flow urine out of the kidney FLOW OF URINE: nephrons (has capillaries coming in)→ collecting ducts (thick tubes) → drain to calices (sing. calyx)→ merge and dump into renal pelvis → drain in ureter ureter 👍 The two layers of the ureter's mucosa are: 1. transitional epithelium = allows for stretching to accommodate the fluctuating volume of urine 2. lamina propria = provides structural support Fun fact ≈ 11-18 calyces in human Renal corpuscle : ○ Glomerulus = specialized capillaries that filter blood The function of the glomerulus is to filter blood plasma, allowing water, electrolytes, and small molecules to pass through into the Bowman's capsule while preventing larger molecules such as proteins and blood cells from leaving the capillaries ○ Kidneys are receiving 25% of your blood flow straight 1. Abdominal Aorta goes to renal arteries (L/R) 2. Branch to segmental arteries that go to different sections of kidneys 3. Branch to interlobar arteries go up renal columns 4. Arcuate arteries (follows arc) 5. Go out cortex → cortical radiate artery 6. Afferent arteriole : tiny branches go to each nephron 7. Glomeruli (us) 8. Efferent arteriole : back to blood stream to provide to rest of kidney 9. Peritubular capillary & Vasa recta 10. Cortical radiate vein 11. Arcuate vein 12. Interlobar vein – drains 13. Renal vein 14. Drains to INFERIOR VENA CAVA There are lymphatic capillaries as well! Renal veins (L/R)  Renal papilla Nephron: each kidney has ≈ 1 million nephrons We are born w/ complete nephrons that just grow larger; if we damage them, we can not replace them TWO REGIONS 1. Renal corpuscle a. Glomerulus b. Glomerular capsule 2. Renal tubule a. Proximal convoluted tubule b. Nephron loop comes back to cortex c. Distal convoluted tubule Juxtaglomerular apparatus = located where the afferent arteriole touches the ascending limb of the nephron loop Nephron Types: Cortical nephrons ○ Most common ○ Makes most urine Juxtamedullary nephrons ○ Make concentrated or diluted urine : during physiological needs Histology Glomerular capsule : double layer of simple squamous epithelium & is continuous ○ Parietal layer = exterior ○ Visceral layer = interior – touches glomerulus (capillary bed) Podocytes = squamous epithelial cells of the visceral layer (help w/ filtration of blood) ○ Capsular space = area between parietal and visceral layers Collects filtrate (filtered liquid from blood) ○ ^^^ Glomerular (Bowman’s) capsule Nephron Tubule Histology ○ Proximal convoluted tubule: simple cuboidal prominent w/ MICROVILLI ○ Nephron loop : descending limb: simple squamous epithelium ○ Nephron loop: thick ascending limb: simple cuboidal no microvilli ○ Most of distal convoluted tubule: simple cuboidal (shorter squat), no microvilli ○ Last part of (^) and all of collecting duct: simple cuboidal some with prominent microvilli Juxtaglomerular apparatus ○ Where efferent & afferent arterioles come together ○ Macula densa = specialized cuboidal epithelial cells in the nephron loop Sense when filtration rate slows in nephron and release nitric oxide (NO) NO* cases capillaries to dilate and increases blood flow to glomerulus → increases filtration in nephron ○ Juxtaglomerular cells = specialized smooth muscle fibers in arteriole Sense blood pressure (volume of blood) in arteriole Release renin (hormone) → increases blood pressure; slow rate of filtrate going in nephron Nephron Functions 1. Glomerular filtration a. Renal corpuscle filters blood plasma b. Prevents blood cells from entering nephron 2. Tubular reabsorption a. Reabsorb useful substances back into the bloodstream  b. Water, ions, nutrients get reabsorbed from tubules and back into capillaries 3. Tubular secretion a. Pump specific wastes into the urine b. Metabolic wastes, toxins, drugs Renal Failure = decrease/cessation of glomerular filtration - Enlarged kidneys - Edema - Metabolic acidosis– acid - Urea accumulation in blood - Calcium deficiency ; when kidneys do not work properly –(kidney produces calcitriol hormone helps body absorb calcium) Hemodialysis = a medical procedure that filters blood to remove waste and excess fluid when the kidneys are no longer functioning properly Peritoneal dialysis = uses peritoneal membrane to filter blood KIDNEY TRANSPLANT! URETERS (2): sit retroperitoneally, go behind urinary bladder and enter into urinary bladder from the bottom(inferior), has no valves Histology: Mucosa: Muscularis Adventitia Adipose (outside) URINARY BLADDER (1) : anterior to rectum; surrounded by peritoneum 3 layers to the urinary bladder - Mucosa (lines the lumen) = transitional epithelium - Submucosa = connective tissues - Muscularis (detrusor muscle) = 3 layers of smooth muscle Bladder contains the internal urethral sphincter URETHRA (1) Men urethra = about 8 inches long Prostatic urethra Membranous urethra Spongy urethra Woman urethra = about 1.5 inches long HISTOLOGY: Mucosa ○ Epithelium varies along length Transitional near bladder stratified/pseudostratified columnar in middle Stratified squamous epithelium near external orifice ○ Muscularis Men: smooth muscle near the PROSTATE, but skeletal inferior to prostate Women: smooth muscle all the way through Micturition (Voiding urine) 1. Stretch receptors in bladder signal the micturition center in the spinal cord a. Occurs when bladder contains 200-400 mL urine  2. Triggers micturition reflex a. Relaxation of the internal urethral sphincter b. Contraction of the detrusor muscle in the bladder c. Inhibition of the external urethral sphincter Takes practice to voluntarily control the external urethral sphincter (override #3) Aging→ Nephrons slow down & can stop functioning You lose 40% of nephrons by 85 Less filtration of blood Less urine formation Prostate enlarges in men ○ May close off urethra (make it difficult to urinate) #1 Why do we urinate? (What is the purpose?) We urinate to help our body get rid of excess waste and maintain water balance. #3 Check all that apply The peritoneum is a serous membrane. The peritoneum is made up of: Areolar connective tissue Simple squamous epithelium #4 What are the names of the capillaries following the efferent arteriole? Peritubular and vasa recta #5 Blood filtrate is captured in the lumen of the Glomerular (Bowman’s) capsule #6 Renal failure is a dangerous condition! A patient’s blood quickly becomes toxic in only a few days without a functioning kidney. Based on what we covered in this lecture so far, list at least four ways in which renal failure may lead to an imbalance of homeostasis in the patient’s body. (*Hint: start by reflecting on the function of the urinary system.) The urinary system has a large effect on the cardiovascular system since it has a job of filtering blood by excreting wastes, removing excess water and solute to regulate blood ions, regulate blood pH level, and has the ability to secrete endocrine hormones. Renal failure can affect a patient's balance of homeostasis in many ways. In renal failure, the kidneys may not be able to excrete excess fluid or electrolytes properly and can lead to fluid retention due to the inability to excrete excess water (edema). Since the kidneys also help maintain the pH balance by excreting hydrogen ions, a nonfunctioning kidney would lead to metabolic acidosis where the body will become to acidic. The kidneys also help detoxify substances and in renal failure, this ability would be impaired and lead to excrete harmful wastes such as ammonia, urea, and creatine out of our bodies properly. Lastly, an impaired kidney would disrupt calcium balance as well. The kidney produces calcitriol hormone to help the body absorb calcium. This will contribute to low calcium levels. As learned from previous lectures, calcium is extremely important for nerve and muscle function and is also stored in our bones to make them strong. #7 The urinary tract is relatively bacteria-free. However, occasionally humans contract urinary tract infections where the bacteria of the intestines (e.g. E. coli) infect the urethra. 1. Why are people with female reproductive organs at a higher risk for developing UTIs? *Hint: remember a UTI is an infection of the urethra or any other part of the urinary system. It is therefore not because of the relative length of the urethra itself. 2. Besides feeling uncomfortable (inflammation/burning sensation) what other organs are at risk during a UTI? 1. The reason why women with reproductive organs are at a higher risk for developing UTIs. Not only is it because the female urethra is anatomically a lot shorter at about 1.5-2 inches while the male's is about 8 inches, the female urethra also is closer to the anus and the proximity can increase the likelihood of getting bacteria in the urethra and to the bladder. 2. The organs at risk during a UTI can include the prostate gland (in males), ureters and the kidneys, which can lead to progression into the bloodstream and can affect multiple other organs like the heart. REPRODUCTIVE SYSTEM Gross Anatomy of the Female Reproductive System: includes organs for creating an oocyte (egg) and sustaining and nurturing the embryo & mammary glands to feet and nurture baby Ovaries→uterine tubes→ lead to uterus (separated from vagina from cervix) → exits through vaginal orifice EXTERNAL ANATOMY: Vulva: opening to reproductive system 2 labia (lips) – ○ region between two labium minora and inside vaginal orifice = vestibule ○ Labia majus (majora) ○ Labia minus External Urethral orifice: opening to urethra/bladder Clitoris (erectile tissue) - opening for the urethra to the urinary system Mons pubis/Mons veneris: padding of adipose tissue that helps cushion and protect pubic symphysis ○ Pubic hair INTERNAL ANATOMY Ovaries (female gonads) : ○ Almond shaped ○ Produce female gametes → secondary oocytes when ovulated & mature into ovum capable of being fertilized by sperm ○ Secrete progesterone, inhibin, relaxin, estrogen ○ Held in place by three sets of ligaments: Broad ligament (fold of peritoneal membrane) to hold the posterior side of ovary in place Ovarian ligament (connect ovaries & uterus) Suspensory ligament = holds ovaries to pelvic wall  Hilum of ovaries = area where blood vessels can enter (at suspensory ligament) HISTOLOGY: Ovaries: Primordial follicles 2 layers 1. Germinal epithelium (inside) = simple cuboidal and simple squamous epithelium 2. Tunica albuginea (inside) = Dense irregular connective tissue (appears white) at cortex: a. Developing oocytes surrounded by follicular cells (simple squamous epithelium) when young, granulosa cells when older Loose connective tissue in medulla In fetus: Oogonia = stem cells for oocytes → ova Primordial Follicle contains primary oocyte holds in meiosis 1 stage until female hits puberty Follicle stimulating hormone & luteinizing hormone will stimulate maturation of primordial follicles into primary follicles every month PRIMARY FOLLICLE = Granulosa cells are cuboidal, 1 - a few layers SECONDARY FOLLICLE = lots of granulosa cells Corona radiada (crown of egg) TERTIARY FOLLICLE = mature follicle antrum is very large & filled w/ follicular fluid → close to ovulation → where the PRIMARY follicle starts initiation of meiosis II & turns into a secondary oocyte at the end of the stage Ejected ovum → secondary oocyte during ovulation & has corona radiata (granulosa ring around it) Corpus luteum (releases hormones) to help prepare for implantation= allows ovulated egg to get implanted in the uterus to get fertilized Corpus albicans remaining scary tissue when egg does not get fertilized PHASES OF OOCYTE Oogonia (stem cells embryo) [2n] → primary oocytes (begin meiosis I) [fetus to tertiary follicle] → secondary oocyte (ovulation) → ovum (prior to fertilization) Uterine tubes/Fallopian Tubes/Oviducts Held in place by peritoneum Help sperm and oocytes reach each other ○ Has lowered immune response ○ Perfect pH Structures help move oocyte/zygote towards uterus (fimbriae) ○ Ciliated simple columnar epithelial tissue = cilia ○ Muscularis layer of smooth muscle = contractions When zygote travels along tube - turns into embryo & then when it reaches the uterus (site of implantation), turns into a mature embryo and into a fetus Uterus: - Fundus of uterus - Body of uterus - Isthmus of uterus - Cervix of uterus HISTOLOGY Perimetrium ○ Visceral peritoneum + broad ligament  Myometrium ○ 3 layers of smooth muscle ○ Produces contractions during childbirth Endometrium ○ Highly vascularized ○ Simple columnar epithelium + areolar CT ○ 2 layers Stratum functionalis = shed during menstruation Stratum basalis = permanent 50-150 mL of blood menstruation Female Reproductive Cycle: Ovarian cycle = events in the ovaries that result in ovulation Uterine cycle (menstruation cycle = changes in endo Vagina = receptacle for the penis Rugae (folds along the wall) Hymen tears open as mucosa fold ruptures from trauma of penis Two layers of smooth muscle that can be contracted Mammary gland = modified sudoriferous glands Multiple alveoli Men can also lactate if exposed to specific hormones (they have mammary glands) Male Reproductive Anatomy Two layers of the scrotum dartos muscle (external): tightens the scrotum cremaster muscle: raises the testis towards the abdomen Leydig cell (interstitial) = make testosterone Nurse cell (support managernic cells) 60%Seminal vesicles = seminal fluid 25% Prostate (gland) = prostatic fluid (food, reverses coagulation– proteolytic enzymes, antibacterial (seminal plasm) enzyme Bulbourethral (Cowper’s) glands = bulbourethral fluids (mucus) Prepuce (foreskin) = retracts during erection HISTOLOGY Erectile tissue have spaces (sinuses) that fill with blood ○ Corpora cavernosa penis ○ Corpus spongiosum penis Ejaculation = Sympathetic reflex (of spinal cord) ○ Internal urethral sphincter (in bladder) closes to prevent urine from escaping ○ Peristalsis along the ductus deferens and urethra propels semen and sperm Birth control: Vasectomy (in male) Tubal Ligation (in female) Aging Female: Menarche = onset of first menses  Menopause = permanent cessation of menses ○ Drop in hormones as ovaries stop producing follicles ○ Ovaries and uterine tubes shrink ○ Bone loss and increased risk of cardiovascular disease Male: Testosterone levels drop Sperm count decreases Prostate enlarges #1 1. What is the difference between sex and gender? 2. Which of these terms are used for sex, and which are used for gender?: male, man, woman, female 1. Sex refers to the biological characteristics a person has which includes the chromosomes, reproductive organs, and hormone levels from hormones being produced. 2. Male and female are used for sex while man and woman are used for gender. Which are gonads? (This is an often mis-used term!) Ovaries Testes #2 If a single cell undergoes meiosis to make gametes, how many cells will it produce? 4 gametes #3 In A Clash of Kings (Book 2 of A Game of Thrones) 12-year-old Sansa Stark awakes to find she has just experienced menarche (her first menstruation). The book describes Sansa waking up with her legs covered in blood and finding blood soaking completely through the blanket, bed sheet, and feather bed mattress. Above is a screen shot of the same scene depicted in the HBO television series. What is wrong with this picture? The volume of blood is too great #4 During a vasectomy the vas deferens are severed to prevent the ejaculation of sperm. Does this affect the volume of semen released? No, there will be no noticeable change in volume Human Development: Prenatal development = the time of gestation from fertilization to birth ○ About 266 days (9 months) Postnatal development = birth until physiological adulthood ○ About 20-25 years old PRENATAL PERIOD : 3 stages 1. Pre-embryonic a. Fertilization b. Cleavage c. Morula and blastocyst d. Implantation e. Gastrulation = formation of the germ layers i. THIS divides pre-embryonic stage & embryonic stage f. Placentation = formation of the placenta 2. Embryonic stage = weeks 3-8 where you are developing organs 3. Fetal stage = Weeks 9-birth! Pre-embryonic Stage Step 1: Starts w/ ovulation of egg → release secondary oocyte (surrounded by corona radiata) = layer of granulosa cells from ovarian follicle that surrounds the oocyte + zona pellucida = protein layer secreted by the oocyte Ovulated eggs survive for 24 hours! Step 2: Fertilization → sperm penetrates the secondary oocyte Fertilization (conception) = sperm and oocyte fuse together (each have 23 chromosome) to create zygote Ejaculated sperm survive for 2-5 days & must swim through a gauntlet of the female reproductive tract to make it to the oviduct – about a 7 hour swim - Female immune system attacks sperm because they do not have the same antigens, less than 0.1% make it to the uterus/to the egg - If there is an egg, they still need to penetrate the corona radiata (layer of cell) On average, 200 sperm reach the oviduct Sperm must break through the cells of the corona radiata ○ Each sperm rams its acrosome (protein to help penetrate) to the corona radiata Acrosomes bursts open and enzymes break off corona radiata and sperm dies ○ Dozens of sperm must do this before a hole in the corona opens up! ONLY ONE sperm may enter the zona pellucida ○ Sperm fuses its cell membrane with the oocyte and dumps its nucleus inside ○ The rest of the sperm remains outside, flagella and egg ○ Initiates oocyte activation = zona pellucida hardens to prevent additional sperm from entering Step 3: nuclei of oocyte and sperm fuse → 46 chromosomes → cells initiate cleavage (undergoes mitosis) 2-cell stage, 4-cell stage, 8-cell stage Step 4: Morula = 12 OR MORE CELLS; turns into a blastocyst once it creates a cavity in the center Step 5: Blastocyst (about day 6) ; the pre-embryo becomes a hollow ball of cells w/ a fluid filled cavity & freed itself from the zona pellucida - Outer wall = trophoblast - Fluid filled cavity = blastocoel - Chunk inside = inner cell mass attached to wall Step 6: implantation, development of placenta & cells of trophoblast embed the wall of uterine cavity - At the posterior wall of fundus/body of uterus - Trophoblasts divide rapidly - Trophoblasts dig in endometrial layer of uterus & cut through capillaries → umbilical cord Placenta releases hormones to tell body to not menstruate (ensures endometrium of uterus does not shed):  - Human chorionic gonadotropin hormone - Estrogen - progesterone Blastocysts: - Trophoblast = outer wall : develops the placenta - Blastocoel (fluid filled) w/ inner cell mass: develops embryo and embryonic membrane Gastrulation: cells of inner cell mass start moving, dividing, and separating to establish the primary germ layers. embryonic disc w/ 3 primary germ layers, types of tissues that will eventually form all body parts Early blastocyst→ hollow ball of cells filled w/ fluid filled cavity Late Blastocyst→ pre-embryo w/ DISK, two layers of cells that become embryo proper 1. amniotic 2. yolk sac ectoderm: outside of the body such as skin, hair, nails, xand the CNS -faces amniotic cavity endoderm: forms the lining of digestive tract, urinary tracts, respiratory system, and the organs of the respiratory and digestive system as well the urinary tracts -faces yolk sac mesoderm: forms muscles, bones, connective tissue, and outside of the spinal cord and organs -middle Human development : Embryonic Period Neurulation – formation of central nervous system (day 17) Step 1: Ectoderm overflying notochord– precursor to spinal cord (thickens to form the plate) Step 2: The neural plate folds inward forming neural groove (day 21) Step 3: The raised sides of the neural groove (space in center) called neural folds grow upward (day 23) Step 4: neural folds fuse to form the neural tube and then develop into the brain and spinal cord forms neural plate → center of ectoderm folds creating notochord → neural cord folds to form neural fold (which becomes the integumentary system) → the space between the folds are called neural groove → neural groove encloses known as neural tube which eventually becomes the CNS Vitamin folate = women can not be short on Melanocytes start in ridge near neural fold; neurulation disorders linked to melanocyte migration - Waardenburg syndrome, did not migrate properly Extraembryonic membranes…. Amnion = surrounds the embryo and makes up the amniotic cavity (inner cell mass of blastocyst) Filled w/ amniotic fluid to help cushion the embryo Yolk Sac = used to help make our first blood cells & gets reabsorbed as gonads Allantois = membrane that forms blood vessels & become part of umbilical cord Chorion = made from trophoblast Fetal Period: Circulation Umbilical cord has artery and vein, vein carries oxygenated blood, artery carries deoxygenated blood Ductus venosus (will become ligament) = shunt between umbilical vein & inferior vena cava Ductus arteriosus (will become ligamentum arteriosum) = allow blood to bypass going through lungs Foramen ovale – opening between right and left atria Embryonic Period: Reproductive System First 6 weeks = same development Bud→ glans penis in male clitoris in female Urogenital groove→ shaft of penis in male labia minora in female (inner folds of vulva) Labioscrotal swelling→ scrotum in male labia majora/majus in female Human Development : Fetal Period to Birth Allometric growth Labor and Delivery : parturition , where fetus expelled Step 1: dilation stage (muscle contraction) - Oxytocin released by posterior pituitary gland stimulates - Ruptured amniotic sac Step 2: Expulsion Step 3: Placental Stage (15 or so minutes) #1 Sperm and ova are similar in terms of ________. Chromosome number #2 As sperm first reach the oocyte, they will contact the Corona radiata #3 Which primary germ layer gave rise to the cells that eventually became the central nervous system? ectoderm