Anatomy and Physiology Lecture Notes PDF

ANATOMY AND PHYSIOLOGY LECTURE Ms. Trinidad Salcedo | 1St Semester | BSN A.Y. 2024 – 2025 I. THE ENDOCRINE SYSTEM Endocrine Glands OVERVIEW Includes the pituitary, thyroid, I...

ANATOMY AND PHYSIOLOGY LECTURE Ms. Trinidad Salcedo | 1St Semester | BSN A.Y. 2024 – 2025 I. THE ENDOCRINE SYSTEM Endocrine Glands OVERVIEW Includes the pituitary, thyroid, Internal Communication parathyroid, adrenal, and pineal glands Nervous & endocrine systems facilitate Mainly secrete hormones long-distance communication ○ Some have Nervous system uses electrical signals non-endocrine ○ Neurotransmitters used for functions communication between one cell and Do not have a duct for another secretion. Endocrine system uses hormones Secretions enter blood or ○ Chemical signaling molecules that travel interstitial fluid in blood Hormones affect target cells ○ Reach most cells of the body ○ Cells with receptors Have widespread effects for that specific hormone Functions of the Endocrine System Other Organs That Have Endocrine Helps maintain homeostasis by regulating: Function Use of calories & nutrients Contains cells that have Secretion of wastes endocrine functions Blood pressure & blood osmolarity Includes the hypothalamus, Growth thymus, heart, kidneys, Fertility & sex drive stomach, small intestine, Lactation liver, adipose tissue, Sleep ovaries & testes Chemical Signaling Target Cells Hormones - chemical messengers used by Hormones travel through the bloodstream endocrine system They can reach almost any cell in the body ○ Most are released into blood Hormones only affect target cell ○ Paracrine signaling-hormone affects Cells with a receptor for a particular hormone neighboring cells Binding of hormone to receptor on target cell ○ Autocrine signaling-hormone affects initiates intracellular signaling same cell that released it Comparison of Nervous & Endocrine Systems ○ Endocrine signaling-hormone travels through blood to affect cells throughout Both nervous and endocrine systems allow control body and communication of the body Neurotransmitters - used by neurons & the They accomplish this in different ways: nervous system ○ Neurotransmitters versus hormones ○ Nervous system is generally faster to Endocrine and Exocrine Glands make a change Chemical secretions exit glands via exocytosis ○ Endocrine system has more widespread Endocrine gland secretion releases product into effects bloodstream or extracellular fluid ○ Endocrine system effects generally last Exocrine gland secretion releases product into duct longer that carries product to a body surface HORMONES TYPES OF HORMONES Steroid hormones - cross cell membrane easily ○ Lipid-based hormones Amine-based hormones - modified amino acids ○ Water-soluble; cannot cross cell membranes ALEXA T. BELIZAR | 1 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Peptide & Protein hormones - made from chains Intracellular Hormone Receptors of amino acids ○ Water-soluble; cannot cross cell Associated with steroid & thyroid hormones membranes ○ Hormone must be lipid-soluble to pass through membrane Steroid Hormones May be in cytosol or nucleus Produced from cholesterol molecules Results in increased transcription and increased Lipid-soluble Hormones protein synthesis ○ Can pass through cell membrane Membrane-bound Hormone Receptors Require transport proteins to travel in blood Ex. Testosterone & Estrogens Associated with water-soluble hormones ○ Amine & peptide hormones Amine Hormones Hormone serves as first messenger in the pathway Made from individual amino acids ○ An intracellular second messenger relays Water-soluble hormones message inside the cell ○ Cannot freely pass through the cell Second Messenger System membrane Do not require transport proteins in blood Hormone binds to receptor in cell membrane Ex. Melatonin, Epinephrine, & Norepinephrine G protein is activated G protein activates adenylyl cyclase Peptide and Protein Hormones Adenylyl cyclase converts ATP to cyclic adenosine monophosphate (cAMP) Chains of amino acids cAMP activates protein kinases Water-soluble hormones Protein kinases phosphorylate proteins ○ Cannot freely pass through the cell Amplification allows a small amount of hormone to membrane cause significant change Do not require transport proteins in blood Phosphodiesterase (PDE) breaks down cAMP Ex. Antidiuretic hormone & Insulin ○ Quickly stops internal cellular changes PRODUCTION OF HORMONES Other second messenger systems may use calcium ions as a second messenger Steroid hormones - made on demand by modifying cholesterol molecules Anatomy of a Steroid Hormone ○ Cannot be stored ○ Not soluble in blood Travel bound to transport proteins when in blood Peptide hormones - translated like other proteins ○ Modified & stored in vesicles until release ○ Soluble in blood Travel in a "free" state Steroid hormones are made on demand in Hormone Receptors endocrine cell Receptors can be ○ Enzymes modify cholesterol during Intracellular or on synthesis the cell surface Secreted into blood & travel bound to a transport Lipid-soluble protein hormone receptors Reach target cells where they are released from - usually intracellular transport protein (cytosol or nuclear) Bind to intracellular receptors within the target ○ This is cell lipid-soluble Anatomy of a Protein Hormone hormones can pass through cell membrane Water-soluble hormone receptors - usually on surface of cell ○ These hormones are usually unable to cross cell membrane ALEXA T. BELIZAR | 2 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Protein hormones - made by rough ER or Connected to anterior pituitary by ribosomes in the endocrine cell hypothalamic-hypophyseal portal system Secreted into blood & travel in a "free" state Posterior Pituitary ○ Do not need transport proteins Reach target cells & bind to receptors on surface of Stores and releases two cell hormones Initiate second messenger systems ○ Oxytocin and Factors Affecting Target Cell Response antidiuretic hormone (ADH) The number of receptors a target cell has influences the ○ Hormones are strength of response produced in Downregulation - decrease in receptor number hypothalamus and ○ Occurs when hormone level is chronically transported to higher posterior pituitary ○ Cells become less sensitive to hormone Oxytocin Upregulation - increase in receptor number ○ Release regulated ○ Occurs when hormone levels are by positive chronically low feedback loop ○ Cells become more sensitive to hormone ○ Responsible for Regulation of Hormone Secretion milk ejection reflex ○ Promotes uterine Most hormones regulated via negative feedback contractions loops ○ Contributes to social bonding behavior ○ As hormone level rises, secretion will slow ○ synthetic forms of oxytocin are used during down or stop labor and delivery to promote uterine Oxytocin is regulated by a positive feedback loop contraction and help delivery proceed ○ Suckling leads to oxytocin release ○ Higher levels of oxytocin will increase rate Antidiuretic Hormone of release ADH - Released in response to high blood Regulation of Hormone Secretion osmolarity ○ The solute concentration of blood Other factors influence hormone release: Conserves body fluids by increasing water reabsorption by kidney ○ Urine becomes darker Can also cause constriction of blood vessels Leads to overall increase in blood pressure Release inhibited by drugs like alcohol ○ Higher amounts of urine produced Diabetes Insipidus (DI) DI - Results from chronic underproduction of antidiuretic hormone (ADH) Without ADH, kidneys do not reabsorb adequate amounts of water DI leads to excessive thirst & increased water Chemical levels within blood consumption ○ Levels of nutrients or ions ○ Osmotic imbalance persists, however, Endocrine system - tropic hormones control due to lack of ADH release of other hormones Ionic imbalances can occur in severe cases of Di Nervous system stimulation HYPOTHALAMUS & PITUITARY Hypothalamus Part of diencephalon of the brain Regulates secretion of hormones from pituitary gland Connected to posterior pituitary gland by infundibulum ALEXA T. BELIZAR | 3 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Anterior Pituitary Pituitary dwarfism ○ Decreased stature due to decreased secretion of GH during childhood Gigantism ○ Substantially increased height due to excessive GH secretion during childhood Acromegaly ○ Excessive GH secretion during adulthood ○ Causes increased growth of cartilage leading to larger hands, feet, and ears. ○ May cause cardiovascular complications due to diabetogenic effect Consequences of decreased secretion of GH depend on the timing If decreased secretion of GH occurs during childhood, it may lead to dwarfism. Decreased secretion of GH during adulthood may Secretion is regulated by tropic hormones from lead to slow healing of the body. hypothalamus Tropic hormones travel from hypothalamus to THE MAJOR HORMONES OF THE BODY anterior pituitary in hypothalamic hypophyseal The Thyroid Gland portal system Produces six hormones: Located anterior to Growth hormone - anabolic hormone that trachea and inferior to promotes protein synthesis and tissue building larynx Thyroid-stimulating hormone - causes release of Two lateral lobes thyroid hormones from thyroid gland connected by isthmus Adrenocorticotropic hormone - stimulates Histology: release of cortisol from adrenal cortex Thyroid follicles - Follicle-stimulating hormone - promotes gamete spherical units of thyroid production ○ Internal cavity Luteinizing hormone - promotes release of sex filled with colloid hormones and initiates ovulation Synthesis & Release of Thyroid Hormones Prolactin - promotes milk production Thyroid hormone (TH) - made by follicular cells ○ Stimulated by TSH from anterior pituitary gland Follicular cells bind iodine to thyroglobulin proteins in colloid Intermediaries are combined to form T3 (triiodothyronine) & T4 (tetraiodothyronine) ○ T4 commonly known as thyroxine Hormones remain in colloid until needed TSH stimulates release of T3 & T4 from follicular Growth Hormone (GH) cells when necessary GH - Release regulated by GHRH & GHIH from Regulation of Thyroid Hormone Synthesis hypothalamus Causes production of insulin-like growth factors Negative feedback regulates (IGFs) in target tissues TH secretion Causes growth via: Low levels of TH stimulate ○ Increased protein synthesis TRH release from ○ Increased lipolysis hypothalamus ○ Increased blood glucose levels TRH stimulates release of TSH from anterior pituitary Growth Hormone Disorders TSH stimulates release of TH In general, Growth Hormone promotes growth of from thyroid gland epiphyseal plate during childhood ○ Leads to elongation of bones ALEXA T. BELIZAR | 4 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Functions of Thyroid Hormones ○ Stimulates calcitriol production to increase absorption of dietary calcium Increase basal metabolic rate (BMR) ○ Cause every cell to increase production of Parathyroid Disorders ATP Hyperparathyroidism = excessive secretion of Promote protein synthesis PTH leads to excessive bone resorption Increase effectiveness of epinephrine and ○ Leads to increased blood levels of calcium norepinephrine resulting in: Increase body temperature Decreased bone density, leading ○ Heat given off due to ATP production to increased fractures Required for adequate growth and development of Reduced responsiveness of skeletal and nervous tissue in childhood nervous system Thyroid Disorders Increased calcium deposits in tissues and organs Goiter - enlarged thyroid Hypoparathyroidism = insufficient production or ○ Caused by accumulation of colloid secretion of PTH Hypothyroidism - insufficient production of thyroid ○ Leads to low blood levels of calcium, hormones causing muscle twitching, cramping, ○ May lead to weight gain and cold convulsions, or paralysis intolerance As blood calcium levels increase, calcitonin is Hyperthyroidism - excessive production of thyroid released and decreases blood calcium levels. hormones As blood calcium levels decrease, parathyroid ○ May lead to weight loss and increased hormone is released and increases blood calcium body temperature levels. Calcitonin The Adrenal Glands Secreted by parafollicular cells Secreted in response to elevated blood calcium levels Decreases blood calcium levels ○ Inhibits osteoclast activity & stimulates osteoblast activity ○ Decreases calcium absorption by the intestine ○ Increases calcium loss in urine Calcium Regulation Calcium plays a role in many biological processes Levels are regulated by hormones Calcitonin from thyroid and parathyroid hormone (PTH) from the parathyroid glands work Triangular glands on top of each kidney antagonistically to regulate calcium levels Covered by capsule Parathyroid Glands Divided into adrenal cortex (superficially) and medulla (deeper) Located on posterior of Adrenal cortex has three zones: thyroid gland ○ 1. Zona glomerulosa Oxyphil cell function is ○ 2. Zona fasciculata unknown ○ 3. Zona reticularis Chief cells secrete parathyroid hormone (PTH) Hormones of the Zona Glomerulosa ○ Secreted in response to low Most superficial region of adrenal cortex calcium levels Secretes mineralocorticoids ○ Increases blood calcium levels Main mineralocorticoid is aldosterone Stimulates osteoclasts that Increases sodium and water reabsorption by kidney breakdown bone matrix releasing ○ Increases blood pressure calcium ○ Involved in renin-angiotensin-aldosterone ○ Inhibits osteoblasts system (RAAS) ALEXA T. BELIZAR | 5 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Hormones of the Zona Fasciculata The Pancreas Intermediate region of adrenal cortex Secretes glucocorticoids Main glucocorticoid is cortisol ○ Released in response to stress ○ Release stimulated by ACTH. ○ Suppresses immune system ○ Stimulates breakdown of stored nutrients for energy Glycogenolysis Lipolysis Gluconeogenesis Hormones of the Zona Reticularis Pancreas Located within abdomen posterior to stomach Deepest region of adrenal cortex Both endocrine & exocrine gland Secretes androgens ○ Exocrine function is to secrete digestive ○ These are male sex hormones enzymes Main androgen secreted is dehydroepiandrosterone Endocrine cells in pancreatic islets (DHEA) ○ Alpha cells - secrete glucagon Supplements testosterone in males ○ Beta cells - secrete insulin Promotes libido in females ○ Delta cells - secrete somatostatin The Adrenal Medulla ○ PP cells - secrete pancreatic polypeptide Releases epinephrine and norepinephrine; Regulation of Blood Glucose collectively called catecholamines ○ Produced by chromaffin cells ○ Considered hormones when released into the blood Considered neurotransmitters at locations where they are released into a synapse ○ Release results in fight-or-flight responses of the sympathetic nervous system Insulin lowers blood glucose by: ○ Stimulating uptake by cells Adrenal Gland Disorders ○ Glycogenesis ○ Lipogenesis Cushing's disease = hypersecretion of cortisol Glucagon increases blood glucose by: ○ Results in hyperglycemia and lipid ○ Glycogenolysis deposits around face and neck ○ Gluconeogenesis ○ Symptoms: Moon-shaped face, buffalo ○ Lipolysis hump on back of neck, rapid weight gains, and hair loss Insulin Mechanism of Action ○ Complications: Increases risk of type 2 diabetes and decreases immunity Addison's disease = hyposecretion of cortisol ○ Results in hypoglycemia and low blood levels of sodium (hyponatremia) ○ Symptoms: May result in general weakness, weight loss, nausea, vomiting, sweating and craving salty foods Insulin stimulates glucose uptake in cells ○ Primary target cells include skeletal muscle cells & adipocytes Binding of insulin leads to increased number of glucose transporters (GLUT) in membrane of target cells ALEXA T. BELIZAR | 6 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER OTHER ORGANS THAT HAVE ENDOCRINE SYSTEM The Liver The Thymus Secretes insulin-like growth factor (IGF) in response to GH Located within mediastinum, superior to heart Produces angiotensinogen Site of T lymphocyte maturation within the ○ Precursor to angiotensin, a hormone immune system involved in increasing blood pressure ○ More active during childhood & decreases Secretes thrombopoietin, a hormone that in size with age stimulates platelet production Secretes thymosins Secretes hepcidins that regulate iron levels ○ Aids in development & differentiation of T lymphocytes II. THE DIGESTIVE SYSTEM The Heart OVERVIEW Secretes atrial natriuretic peptide (ANP) Functions of the Digestive System ○ Decreases blood pressure in response to increased blood volume or increased blood 1. Ingestion - intake of food & drink pressure 2. Digestion - breakdown of ingested material ○ Increases sodium & water loss by the 3. Secretion - production & release of fluids & kidneys (via urine), to decrease blood enzymes associated with digestive activity volume and blood pressure 4. Mixing & propulsion - mixing with secretions & moving through digestive system The Gastrointestinal Tract 5. Absorption - absorbing nutrients in ingested Endocrine cells located in walls of stomach & small material into the blood intestine 6. Excretion - elimination of wastes via fecal material Hormones aid in digestion Organs of the Digestive System ○ Gastrin stimulates release of hydrochloric acid by stomach Digestive (GI) tract ○ Other hormones aid in regulation of glucose metabolism Series of organs through which ingested material moves The Kidneys Breaks down & absorbs nutrients Produce renin that is involved in the Accessory digestive organs renin-angiotensin aldosterone system (RAAS); regulation of blood pressure Not part of GI tract Secretes calcitriol that aids in regulation of calcium Have function associated with homeostasis digestive activity Produces erythropoietin (EPO) Liver, pancreas, gallbladder, ○ Stimulates production of red blood cells salivary glands Adipose Tissue Connections to other body systems Hormones are collectively called adipokines Digestive system works cooperatively with other ○ Involved in metabolism & nutrient storage systems Secretes the hormone leptin ○ Cardiovascular system absorbs nutrients ○ Binds to neurons within brain to cause and circulates them following digestion feeling of satiety after a meal ○ Specific endocrine cells secrete ○ Helps reduce appetite hormones that regulate digestive activity Secretes the hormone adiponectin ○ Skin is involved in production of vitamin D ○ Reduces cellular insulin resistance Gastrointestinal The Skin Continuous tube divided into different organs Involved in production of vitamin D Sections of GI tract: Absorbs UV radiation to convert cholesterol into 1. Mouth inactive vitamin D 2. Pharynx Can be converted into active vitamin D by liver and 3. Esophagus kidneys 4. Stomach Active vitamin D is involved in absorption of dietary 5. Small intestine calcium and immune functions 6. Large intestine (colon) 7. Anus ALEXA T. BELIZAR | 7 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Muscularis Longitudinal & circular layers of smooth muscle ○ Stomach has additional oblique layer Most sections of the Gl tract contain two layers in the muscularis ○ Inner circular layer of muscularis ○ Outer longitudinal layer of muscularis Stomach contains additional oblique layer of muscularis for a total of three layers Contractions of muscularis propel food forward, mix and churn ingested food Accessory Organs Muscularis at ends of tract is made of skeletal muscle Accessory Muscles - Aid in the breakdown of ○ Gives voluntary control of swallowing & ingested material defecation Accessory organs include: 1. Teeth Serosa 2. Tongue 3. Salivary glands Outermost layer; thin layer of connective tissue 4. Pancreas Superficial wall layer farthest from the lumen 5. Liver Composed of connective tissue 6. Gallbladder Helps anchor arteries, veins & nerves to Gl tract wall GENERAL GROSS AND MICROSCOPIC ANATOMY Referred to as serosa only within abdominal cavity OF THE GASTROINTESTINAL (GI) TRACT Referred to as adventitia for the mouth, pharynx, and esophagus Microscopic Structure of the Gl Tract Lumen - interior space of Gl tract Mechanical versus Chemical Digestion Gl tract wall consists of 4 layers: Mechanical digestion - uses force generated by Mucosa muscles to digest nutrients ○ Begins with chewing (mastication) in the Innermost layer; epithelial tissue, lamina propria, mouth muscularis mucosae ○ Muscularis layer is involved in Non-keratinized stratified squamous epithelium mechanical digestion lines mouth, pharynx, esophagus & anal canal Chemical digestion - utilizes enzymes & other Simple columnar epithelium lines stomach & secretions to break down ingested material intestines ○ Other secretions come from salivary Epithelial tissue is supported by lamina propria glands, stomach, liver, pancreas, and ○ Contains blood, lymphatic vessels, and gallbladder mucosa-associated lymphoid tissue (MALT) Peristalsis Muscularis mucosa forms rugae in stomach & Sequential, alternating small intestine to increase surface area waves of contraction & Goblet cells secrete mucus for lubrication relaxation by layers of Enteroendocrine cells secrete hormones in muscularis response of nutrients or pathogens Propels food forward within Submucosa tract Helps mix food with Connective tissue with blood vessels, lymphatics, digestive juices and nerves Lies deep to the mucosal layer & connects the Nerve Supply mucosa to muscularis layer CNS initiates activities such as salivation Composed of dense connective tissue with blood & ○ Also responsible for sight, taste, smell, and lymphatic vessels feel of ingested materials Contains submucosal glands that release digestive Enteric nervous system innervates Gl tract secretions ○ Myenteric plexus controls movements of Location of submucosal plexus muscularis ○ Helps regulate digestive secretions & ○ Submucosal plexus controls digestive reacts to presence of food secretions ALEXA T. BELIZAR | 8 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Autonomic nervous system Tongue ○ Sympathetic - decreases GI motility & secretion Made of skeletal muscle ○ Parasympathetic - increases GI motility & Functions in ingestion, secretion sensation, swallowing, and speech Blood Supply Papillae contain taste buds Provides nutrients & removes wastes from Gl tract Lingual frenulum anchors and accessory organs tongue Absorbs protein & carbohydrate nutrients Salivary Glands ○ Lipids absorbed by unique lymphatic capillaries called lacteals Secrete saliva into oral cavity Hepatic portal system ○ Watery secretion ○ Veins that drain intestine carry absorbed that contains nutrients to liver first enzymes ○ Liver processes & detoxifies incoming Three pairs of salivary nutrients before they enter general glands: circulation ○ Parotid glands ○ Submandibular The Peritoneum glands ○ Sublingual glands Saliva Begins chemical digestion & moistens food ○ Secretion regulated by autonomic nervous system (ANS) Salivary amylase breaks down carbohydrates ○ Infants secrete salivary lipase to break Serous membrane that holds abdominal organs in down lipids in breastmilk position Bicarbonate & phosphate ions buffer acidic foods ○ Composed of parietal & visceral layers ○ IgA & lysozyme prevent microbial ○ Peritoneal cavity contains peritoneal fluid infection in mouth to reduce friction between the layers ○ Histostatin helps speed wound healing Intraperitoneal - organs within peritoneum Teeth Retroperitoneal - organs behind peritoneum Four major folds - lesser omentum, greater omentum, transverse mesocolon, mesentery proper THE MOUTH, PHARYNX, AND ESOPHAGUS Mouth Also known as oral cavity ○ Framed by cheeks, tongue, and palate Entrance to Gl tract bordered by lips (labia) Muscles involved in Organs similar to bones, used to tear, grind & mastication (chewing) mechanically break down food begin mechanical Deciduous teeth are replaced by permanent teeth digestion ○ Eight incisors - used for biting & cutting Hard palate made of bone provides hard surface to ○ Four cuspids (canines) - used for push food during swallowing piercing Soft palate made of skeletal muscle elevates ○ Eight premolars - used for mashing & during swallowing grinding Uvula directs ingested materials inferiorly ○ Twelve molars - used for crushing Adult - total of 30 (no wisdom tooth yet) or 32 Children - total of 20 ALEXA T. BELIZAR | 9 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Anatomy of a Tooth Histology of the Esophagus Socket lined by Mucosa contains non-keratinized stratified gingivae (gums) squamous epithelium Periodontal ligaments ○ Protects against friction from food moving anchor teeth in through esophagus sockets Muscularis varies in composition throughout the Crown above esophagus gumline; root ○ Upper third: skeletal muscle embedded within ○ Middle third: combination of skeletal & socket smooth muscle Pulp cavity contains ○ Lower third: smooth muscle nerves & blood Outer adventitia due to esophagus located outside vessels that run through root canal to bone of abdominal cavity Bone-like dentin covers pulp cavity Stomach In crown, dentin is covered by enamel Pharynx (Throat) Hollow, muscular organ that continues chemical & Funnel-like passageway mechanical digestion for food and air ○ Very little Sectioned into absorption nasopharynx, occurs in oropharynx & stomach laryngopharynx Regions of stomach: Oropharynx is lined by ○ Cardia, fundus, stratified squamous body, antrum, epithelium pylorus ○ Pylorus divided into antrum & canal Swallowing ○ Pyloric sphincter regulates movement into Voluntary phase - tongue small intestine moves up & back; pushes Muscularis contains additional oblique layer bolus into oropharynx; can be ○ Mixes food with gastric juice to become consciously controlled chyme Pharyngeal phase - uvula & Cardia - region where food enters stomach soft palate reflexively elevate Fundus - increases capacity of stomach to close nasopharynx Pylorus - connects stomach to duodenum Esophageal phase - bolus Gastric rugae - allows stomach to expand when full enters esophagus & peristalsis begins Pharyngeal & esophageal phases are involuntarily controlled Esophagus Flat, muscular tube that connects pharynx to stomach Upper esophageal Muscularis contains additional oblique layer sphincter relaxes to Mucosa contains gastric pits allow movement into Gastric glands secrete gastric juice esophagus ○ Parietal cells secrete hydrochloric acid & Peristalsis moves intrinsic factor bolus through ○ Chief cells secrete pepsinogen esophagus ○ Mucous neck cells secrete mucus Lower esophageal sphincter relaxes to allow ○ Enteroendocrine cells secrete hormones entry into stomach ○ Fails when gastroesophageal reflux disease (GERD) occurs ALEXA T. BELIZAR | 10 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Phases of Gastric Secretion Enzymes in small intestine break bonds to yield individual amino acids Cephalic phase - begins when body is Small Intestine alerted by the smell, Chyme enters from taste, sight, or thought stomach of food Site of most digestion & Gastric phase - absorption of nutrients activated by nervous & Divided into three endocrine system when sections: food enters stomach 1. Duodenum ○ Results in receives increased gastric secretion & motility secretions Intestinal phase from biliary apparatus ○ Excitatory - duodenum increases gastric 2. Jejunum secretion 3. Ileum ○ Inhibitory enterogastric reflex inhibits Ileocecal sphincter regulates movement into large gastric secretion & movement when small intestine intestine is full The Duodenum Gastric Mucosa Site of majority of chemical digestion Gastric Mucosa - Protects stomach from Receives secretions from gallbladder, pancreas & self-digestion due to highly acidic conditions liver ○ Mucous, bicarbonate & stem cells rapidly Liver produces bile that drains from hepatic ducts divide into common hepatic duct Helps regulate gastric emptying Common hepatic duct unites with cystic duct of ○ Acidic chyme slows gastric emptying to gallbladder to form common bile duct prevent duodenum becoming Common bile duct unites pancreatic duct to form overwhelmed hepatopancreatic ampulla Intrinsic factor - secretion that allows for vitamin Empties bile & pancreatic juice into duodenum B12 absorption ○ Sphincter of Oddi regulates release into Gastric Hormones duodenum The Biliary Apparatus Liver and gallbladder contribute bile to duodenum Head of pancreas is in curve of duodenum Secretions from all three accessory organs empty into duodenum Jejunum and Ileum Figure Gastrin promotes Gl tract motility & gastric juice secretion Jejunum is the middle Histamine promotes HCl secretion into stomach segment of small intestine Serotonin causes contraction of stomach muscles ○ No clear border for churning separates it from Somatostatin decreases Gl tract motility & ileum secretion Ileum is longest, terminal Ghrelin influences feelings of hunger & satiety segment of small intestine ○ Thicker & more Protein Digestion vascular than other segments ○ Joins the cecum at the ileocecal junction/ Enzymes cannot easily access & break bonds of sphincter highly folded proteins HCl in gastric juice denatures proteins making peptide bonds accessible to enzymes Pepsin cuts proteins into shorter polypeptides ALEXA T. BELIZAR | 11 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Histology of the Small Intestine Teniae coli extend the length of large intestine Small Intestine - Circular folds, villi, and microvilli ○ Contractions form increase surface area for absorption of nutrients haustra ○ Circular folds visible at gross level Motility in large intestine ○ Villi (microscopic) contain capillaries & ○ Haustral lacteals for absorption of nutrients contractions - aid in ○ Microvilli (microscopic) make up brush water absorption border on epithelial cell ○ Mass movement - Contains enzymes for digestion forces contents Intestinal glands produce intestinal juice that help toward rectum neutralize acidic chyme Gastrocolic Duodenal glands secrete alkaline mucus to protect reflex - gastric activity increases mucosa colon activity Intestinal MALT provides immune protection Valsalva's maneuver - increased abdominal Mechanical Digestion in the Small Intestine pressure aids in fecal elimination Wall of the Large Intestine Two motility patterns of small intestine: ○ Peristalsis - pushes contents forward Simple columnar ○ Segmentation - mixes contents locally epithelium primarily line the Does not propel them forward mucosa Gastroileal reflex - increased stomach activity Absorbs water, salts, and leads to increased contraction of ileum vitamins ○ Pushes intestinal contents forward into Mucosa contains deep cecum to allow further gastric emptying intestinal glands Large Intestine ○ Numerous goblet cells Completes absorption of produce mucus to reduce friction nutrients & water, forms Each person contains unique bacterial composition fecal material & helps within large intestine synthesize some Gastric ulcers have been associated with bacterial vitamins infections of the gastric mucosa Contains bacteria that aid in function ACCESSORY ORGANS IN DIGESTION: THE LIVER, Frames the small PANCREAS, AND GALLBLADDER intestine within abdomen The Accessory Organs of Digestion Regions of the large intestine: Accessory organs of digestion include the liver, gallbladder, ○ Cecum, and pancreas Gallbladder ascending Liver produces bile & colon, transverse colon, descending colon, filters blood from sigmoid colon, rectum, and anus intestines ○ Appendix is attached to cecum Gallbladder stores & concentrates bile Pancreas produces pancreatic juice that contains digestive enzymes Functions of Liver Detoxifies nutrients brought to liver from absorbing Flexures are bends in the large intestine digestive organs ○ Right hepatic flexure or right colic flexure Processes drugs & toxins within body ○ Left splenic flexure or left colic flexure Stores iron Rectum holds fecal material until eliminated Produces bile ○ Internal & external anal sphincters regulate Produces plasma proteins release of feces Breaks down old red blood cells, decomposes ○ Internal anal sphincter is smooth muscle; hemoglobin, and excretes the bilirubin waste in the external anal sphincter is skeletal muscle bile ALEXA T. BELIZAR | 12 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Liver Pancreas Retroperitoneal organ at posterior of abdomen Located in right upper quadrant of abdomen Both endocrine & exocrine gland 2nd largest organ of adult human body Head is nestled into C-shaped duodenum Divided into right, left, caudate & quadrate lobes Pancreatic acini secrete digestive enzymes Anchored to abdominal wall by ligamentum teres ○ Released via pancreatic and accessory and falciform, coronary, and lateral ligaments ducts Porta hepatis - site of hepatic artery, hepatic portal Biliary System vein, and common bile duct Vessels that carry secretions of pancreas and bile Histology of the Liver from liver and gallbladder Organized into lobules Right and left hepatic ducts of liver carry bile Microscopic lobules receive blood from hepatic Unite to form common hepatic duct portal vein and hepatic artery Common hepatic duct merges with cystic duct to ○ Blood flows through sinusoids to the form common bile duct central veins Common bile duct unites with pancreatic duct to Hepatic artery delivers oxygen form hepatopancreatic ampulla and nutrients to hepatocytes Release of bile and digestion enzymes occurs at Hepatic portal vein delivers major duodenal papilla blood from intestinal absorption Pancreatic Juice for detoxification ○ Central veins form hepatic veins and Composed of water, sodium bicarbonate, digestive return blood to inferior vena cava enzymes ○ Sodium bicarbonate buffers chyme Fat Emulsification ○ Protein-digesting enzymes produced in Hepatocytes produce bile in liver, which is stored in inactive form to prevent self-digestion the gallbladder Activated by acidity of chyme in Bile emulsifies large lipid globules duodenum ○ Separates them into smaller globules Pancreatic secretion stimulated by entry of chyme ○ Makes them more accessible to digestive into the duodenum enzymes ○ Leads to secretin and cholecystokinin Bile canaliculi drain bile from liver lobules into bile (CCK) release that increases secretion of ducts pancreatic juice ○ Bile ducts and branches of hepatic artery CHEMICAL DIGESTION AND ABSORPTION and hepatic portal vein form portal triads Digestion and Absorption Gallbladder Digestion begins in the Located on posterior mouth surface of liver Continues as food moves Stores & concentrates through Gl tract bile Most absorption (~90%) Releases bile when occurs in the small intestine necessary via cystic Indigestible food may be duct for digestion of eliminated as feces or fats. metabolized by bacteria within Gl tract ○ Provides nutrients for both bacteria and human body ALEXA T. BELIZAR | 13 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Nucleic Acid Digestion Pancreatic enzymes involved in nucleic acid digestion: ○ Deoxyribonuclease - digests DNA ○ Ribonuclease - digests RNA Brush border enzymes involved: ○ Nucleosidases, phosphatases Carbohydrate Digestion Absorption Carbohydrates must be Digestion converts ingested materials into digested into molecules small enough for absorption monosaccharides for Absorption occurs through absorption ○ Active transport, simple diffusion, ○ Common facilitated diffusion, secondary active monosaccharides: transport, and endocytosis Glucose, fructose, Monomers of carbohydrates, proteins, and nucleic or galactose acids are absorbed via blood capillaries Enzymes involved in Monomers of lipids are absorbed through lacteals carbohydrate digestion (lymphatic systems) ○ Amylases in Minerals and electrolytes are absorbed almost saliva & completely pancreatic juice ○ Calcium absorption is regulated by PTH help digest ○ Iron absorption is dependent on the body's starches need for iron Cannot digest cellulose (fiber) Fat-soluble vitamins A, D, E, and K are absorbed ○ Brush border enzymes in wall of small by lacteals along with lipids intestine Water-soluble vitamins absorbed by blood Alpha-dextrinase, lactase, Water absorption occurs primarily in small maltase, and sucrase intestine & remaining occurs in large intestine ○ Lack of water reabsorption leads to Protein Digestion diarrhea Begins with acid in stomach Inputs and Outputs of Digestive System Most enzymes are produced in an inactive state to prevent self-digestion Digestive system takes in water & nutrients ○ Pepsin - produced by stomach Digestive system secretes saliva, bile, gastric juice, ○ Pancreatic enzymes: and pancreatic juice to digest nutrients Trypsin, carboxypeptidase, Most of these secretions are reabsorbed in small chymotrypsin, elastase and large intestines ○ Brush border enzymes Very little is lost in fecal material Lipid Digestion Carbohydrate Absorption Bile aids in lipid digestion by emulsifying lipids Carbohydrates are absorbed as ○ Breaks them up to allow faster digestion monosaccharides Enzymes involved in lipid digestion: ○ Absorbed into mucosal cells by secondary ○ Lingual lipase begins process in mouth active transport with sodium at apical ○ Gastric lipase continues in stomach membrane ○ Pancreatic lipase accomplishes most lipid ○ Facilitated diffusion allows digestion monosaccharides to enter blood capillaries Breaks triglyceride into (at basement membrane) monoglyceride and two fatty Indigestible carbohydrates (e.g., cellulose) acids eliminated in feces ALEXA T. BELIZAR | 14 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Protein Absorption Water Absorption Proteins absorbed as amino acids ~7L of water are reabsorbed daily by digestive ○ Dipeptides and tripeptides enter mucosal system cells via secondary active transport with Water absorption and reabsorption occurs via sodium at apical surface osmosis ○ Broken down into individual amino acids ○ As nutrients and other solutes are within the epithelial cells absorbed, osmotic gradient is established ○ Amino acids enter capillaries via ○ Water moves in the direction of greater diffusion solute concentration Most water reabsorption occurs in small Lipid Absorption intestine (90%) ○ Remainder occurs in large intestine Dietary fats broken down to (10%) long-chain fatty acids, monoglycerides, and glycerol Bile salts encase them in micelles for absorption through mucosal epithelium Fatty acids and monoglycerides reform triglycerides within epithelial Other Nutrients cells Gluconeogenesis - process of converting ○ Mixed with non-glucose molecules into glucose phospholipids and cholesterol to form ○ Pyruvate, lactate, glycerol, or amino acids chylomicrons can be converted Chylomicrons absorbed via lacteals ○ Occurs primarily in liver Nucleic Acid Absorption Glycogenesis - formation of glycogen to store glucose Nucleic acids broken down into pentose sugars, ○ Stored in liver & cardiac muscle nitrogenous bases, and phosphate ions Glycogenolysis - process of breaking down ○ Absorbed by mucosal cells via active glycogen transport at apical surface ○ Liver breaks down glycogen & releases it ○ Enter capillaries to be absorbed by blood into blood Mineral Absorption Blood glucose Homeostasis Electrolytes are primarily absorbed by active Glycogenesis and glycogenolysis help maintain blood transport glucose levels within a homeostatic range ○ Iron is absorbed by mucosal cells and ○ Glycogenesis lowers blood glucose levels bound to ferritin for storage when elevated Only enter blood when iron levels ○ Glycogenolysis increase blood glucose are low levels when low Calcium absorption is dependent on blood levels of calcium ○ PTH stimulates absorption of calcium and production of Vitamin D Vitamin Absorption Fat-soluble vitamins (A, D, E, and K) are absorbed with dietary lipids via lacteals Water-soluble vitamins (B and C) are absorbed via block capillaries ○ Intrinsic factor is secreted by the stomach and aids in the absorption of vitamin B12 ALEXA T. BELIZAR | 15  FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER III. METABOLISM AND NUTRITION Body captures released energy & converts it into ATP OVERVIEW ○ Some energy lost as heat given off by Metabolic Reactions reactions ] ○ Cells release energy later by breaking Catabolic reactions - breakdown reactions that bond between second and third phosphate release energy. Cells can capture energy and groups convert it into ATP ○ Cells constantly cycle among ATP, ADP, Anabolic reactions - smaller molecules joined to and Pi form larger molecules. Utilizes energy and Energy Sources molecules formed by catabolic reactions Metabolism - the sum of all the chemical reactions Glucose is most common energy source that occur in the body. Chemical reactions in the ○ Excess is stored as glycogen or converted body's cells that change food into energy to triglycerides Anabolism - constructive processes in metabolism Dietary lipids also can be used to form ATP that build larger molecules from smaller ones, Amino acids from proteins can be used to form requiring energy input. ATP if necessary - Generally release energy Nucleic acids are typically used to create new Catabolism - destructive process that breaks down nucleic acid molecules, not ATP larger molecules into smaller ones, releasing Anabolic Reactions energy for cellular activities. - Typically use energy Join smaller molecules to form larger molecules ○ Monosaccharides join to form Reactions are coupled in many instances to polysaccharides maintain balance ○ Fatty acids join to form triglycerides ATP is the energy currency of the body and its cells ○ Amino acids join to form proteins ○ Excess energy is stored as glycogen or ○ Nucleotides join to form nucleic acids triglycerides Requires energy input Stored for later use New molecules formed allow growth and repair of Energy in the Body tissues and communication Enzymes and Reactions Enzymes - proteins that function as biological catalysts ○ Increase the rate of a chemical reaction Cofactors - non-protein (vitamins & minerals) molecules that bind to enzymes & enable their activity Many reactions involve electron transfer ATP is the energy currency of the cell ○ Oxidation reactions - occur ○ It can be produced in cytosol or when electrons are lost mitochondria ○ Reduction reactions - occur Cells break down ATP when energy is needed when electrons are gained Excess energy is stored as glycogen or adipose ○ Oxidation-reduction reactions - the coupling of the two reactions together Adenosine Triphosphate (ATP) Redox Reactions ATP consist of adenine, ribose, and three Many food molecules are phosphate groups oxidized to produce ATP Bond between second & third phosphate groups Electrons that are lost are used is high energy to reduce electron carriers Catabolic enzymes break bond to release energy ○ Common electron ○ Yields adenosine diphosphate (ADP) & an carriers are individual phosphate group Nicotinamide adenine Catabolic Reactions dinucleotide (NAD) & ○ Flavin adenine Break down large molecules into smaller subunits dinucleotide (FAD) Release energy within chemical bonds ○ Reduced to form NADH & FADH2 ALEXA T. BELIZAR | 16 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER MACRONUTRIENTS AND METABOLISM Oxygen accepts electrons & H+ ions & forms water Called oxidative phosphorylation due to energy Cellular Respiration of Glucose coming from oxidation of glucose Cellular respiration produces ATP for cells Carbohydrate Metabolism ○ Breaks down glucose to release stored energy ○ Energy is used to form ATP Four phases: ○ Glycolysis - glucose is broken down to produce energy. It produces two molecules of pyruvate, ATP, NADH & water Takes place in cytoplasm ○ Pyruvate oxidation Takes place in mitochondrial matrix ○ Citric acid cycle Takes place in mitochondrial matrix ○ Electron transport chain Takes place along inner mitochondrial membrane Glycolysis Energy consuming phase requires initial investment of 2 ATP Energy releasing phase produces 4 ATP ○ Glucose + 2ATP + 2NAD+ + 4ADP + 2Pi → 2 Pyruvate + 4ATP + 2NADH + Each molecule of glucose yields ~30-36 molecules 2H+ of ATP ○ Net yield of two ATP, Other Nutrients two pyruvate, and two NADH Gluconeogenesis - process of converting Pyruvate enters citric acid non-glucose molecules into glucose cycle if oxygen is present ○ Pyruvate, lactate, glycerol, or amino acids Pyruvate converted to other molecules (lactic acid, can be converted ethanol) via fermentation if oxygen not sufficiently ○ Occurs primarily in liver present Glycogenesis - formation of glycogen to store Glycolysis is the process of oxidizing glucose to glucose produce pyruvate ○ Stored in liver & cardiac muscle Glycogenolysis - process of breaking down Citric Acid Cycle glycogen ○ Liver breaks down glycogen & releases it Pyruvate molecules further oxidized in into blood mitochondrial matrix to form acetyl CoA Triglycerides (fats) ○ Carbon dioxide produced as byproduct ○ Lipids broken down during lipolysis can be Acetyl CoA will enter citric acid cycle used for cellular respiration Yields two ATP, six NADH, and two FADH2 in total Glycerol head can be used in glycolysis Oxidative Phosphorylation Fatty acids can be converted into Electron carriers NADH and FADH, donate acetyl CoA for use in citric acid electrons to ETC cycle Enzyme complexes use energy in electrons to ○ Excess carbohydrates converted to lipids pump hydrogen ions into intermembrane space by lipogenesis for storage Hydrogen ions diffuse back into matrix, ATP synthase uses energy to create ATP ALEXA T. BELIZAR | 17 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER Protein ○ Storage of glucose as glycogen & ○ Broken down to amino acids that are triglycerides slows down usually used to make new proteins ○ Glycogen will be broken down to maintain ○ Excess amino acids converted to glucose stable glucose levels or triglycerides for storage ○ Stimulated by glucagon release ○ Gluconeogenesis also increases blood Blood Glucose Homeostasis glucose level Glycogenesis and glycogenolysis help maintain blood glucose levels within a homeostatic range ○ Glycogenesis lowers blood glucose levels when elevated ○ Glycogenolysis increase blood glucose levels when low Urea Cycle Urea cycle - eliminates excess nitrogen from breakdown of amino acids ○ Produces urea from nitrogenous wastes to prevent toxic buildup of nitrogen ○ Deamination - converts amine group of amino acids into ammonia ○ Transamination - exchange of amine group or ammonium ion for keto group Starvation Forms one molecule that can enter citric acid cycle & 1 that Starvation - Occurs when body is deprived of enters urea cycle nourishment for extended periods of time ○ Produces ammonium ion Priority is to provide enough glucose for the Can be combined with carbon brain dioxide to form urea & water ○ Glycolysis decreases in cells that can use alternate energy sources METABOLIC STATES OF THE BODY ○ Fatty acids & ketones are used to Absorptive State provide energy Muscle cells may be broken down for Absorptive State - gluconeogenesis occurs after a meal when body is ENERGY AND HEAT BALANCE digesting & absorbing Metabolic Rate nutrients Also called the "fed" Difference between the amount of energy state consumed and the amount of energy expended by Insulin release leads the body to uptake of glucose Basal metabolic rate - the amount of energy used by muscle, liver, and by the body at rest in the postabsorptive state adipose tissue ○ Reflects energy needed for basic daily ○ Used for ATP production if energy is functions required shortly after absorption ○ Increases with increased physical activity Excess glucose can be stored as glycogen or muscle mass ○ Limited capacity to do so ○ Decreases with age as muscle mass Excess glucose and fat stored as triglycerides if not decreases used or stored as glycogen NUTRITION AND DIET Postabsorptive State Food Metabolism Postabsorptive State - Also known as fasting Nutritional Calorie - the amount of heat required to state raise 1 kilogram of water by 1 degree Celsius Occurs after food from last meal has been digested, ○ Not equivalent to physical sciences calorie absorbed & stored Physical sciences calorie = the Glucose level decreases as glucose is used and amount of heat required to raise 1 cleared from blood gram of water by 1 degree Celsius ALEXA T. BELIZAR | 18 FINALS | ANATOMY & PHYSIOLOGY 1ST SEMESTER ○ Nutritional calorie = 1 kilocalorie (1000 Minerals calories) Carbohydrates & proteins = 4 (nutritional) calories Inorganic compounds that ensure proper body per gram functioning Fats = 9 (nutritional) calories per gram Gained via the diet Examples include potassium, sodium, calcium, Regulating Caloric Intake phosphorus, magnesium, and chloride Typically, a body requires 1,500-2,000 calories per ○ Aid in functions such as establishing day membrane potentials, muscle contraction, ○ Varies depending on body mass, muscle synaptic transmission, and bone mass, age, activity level & exercise remodeling intensity/duration At higher levels, can be toxic ○ Not directly correlated with body mass IV. THE URINARY SYSTEM index (BMI) Goal is to intake calories equivalent to BMR plus (RENAL SYSTEM - EXCRETORY SYSTEM) calories used for exercise Functions of Urinary System Satiety center is in central nervous system (CNS) & regulates hunger Production, storage & transportation of urine