Essentials of Human Anatomy Physiology Elaine N Marieb

The Digestive System and Body Metabolism · Digestion · Breakdown of ingested food · Absorption · Passage of nutrients into the blood · Metabolism · Production of cellular energy (ATP) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 14. 1

Organs of the Digestive System · Two main groups · Alimentary canal – continuous coiled hollow tube · Accessory digestive organs Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Organs of the Digestive System Figure 14. 1 Copyright © 2003 Pearson Education, Inc.

Organs of the Alimentary Canal · Mouth · Pharynx · Esophagus · Stomach ·

Mouth (Oral Cavity) Anatomy · Lips (labia) – protect the anterior opening · Cheeks – form the lateral walls · Hard palate – forms the anterior roof · Soft palate – forms the posterior roof · Uvula – fleshy projection of the soft palate Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14. 2 a Slide 14. 4

Mouth (Oral Cavity) Anatomy · Vestibule – space between lips and gums · Oral cavity – area contained by the teeth · Tongue – attached at hyoid and styloid processes of the skull, and by the lingual frenulum Figure 14. 2 a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 14. 5

Mouth (Oral Cavity) Anatomy · Tonsils · Palatine tonsils · Lingual tonsil Figure 14.

Processes of the Mouth · Mastication (chewing) of food (mechanical) · Mixing masticated food with saliva · Initiation of swallowing by the tongue · Allowing for the sense of taste · (Add this bullet)Chemical breakdown of carbohydrates Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 14. 7

Pharynx Anatomy · Nasopharynx – not part of the digestive system · Oropharynx – posterior to oral cavity · Laryngopharynx – below the oropharynx and connected to the esophagus Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14. 2 a Slide 14. 8

Pharynx Function · Passageway for air and food · Food is propelled to the esophagus by two muscle layers · Longitudinal inner layer · Circular outer layer · Food movement is by alternating contractions of the muscle layers (peristalsis) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 14. 9

Esophagus · Runs from pharynx to stomach through the diaphragm · Conducts food by peristalsis (slow rhythmic squeezing) · Passageway for food only Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Layers of Alimentary Canal Organs · Mucosa · Innermost layer · Moist membrane · Surface epithelium · Small amount of connective tissue (lamina propria) · Small smooth muscle layer Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Layers of Alimentary Canal Organs · Submucosa · Just beneath the mucosa · Soft connective tissue with blood vessels, nerve endings, and lymphatics Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Layers of Alimentary Canal Organs · Muscularis externa – smooth muscle · Inner circular layer · Outer longitudinal layer · Serosa · Outermost layer – visceral peritoneum · Layer of serous fluid-producing cells Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Layers of Alimentary Canal Organs Figure 14. 3 Copyright © 2003 Pearson Education, Inc.

Stomach Anatomy · Left side of the abdominal cavity · Food enters at the

Stomach Anatomy · Regions of the stomach · Cardiac region – near the heart · Fundus · Body · Pylorus – funnel-shaped terminal end · Food empties into the small intestine at the pyloric sphincter Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Stomach Anatomy · Rugae – internal folds of the mucosa · External regions ·

Stomach Anatomy Figure 14. 4 a Copyright © 2003 Pearson Education, Inc. publishing as

Stomach Functions · Storage tank for food · Site of food breakdown (mechanical) · Chemical breakdown of protein begins · Delivers chyme (processed food) to the small intestine Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Small Intestine · Body’s major digestive organ · Site of nutrient absorption into the blood · Muscular tube · Suspended from the posterior abdominal wall by the mesentery Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Subdivisions of the Small Intestine “Dogs Just Itch!” · Duodenum · Attached to the stomach · Curves around the head of the pancreas · Jejunum · Attaches to duodenum · Ileum · Extends from jejunum to large intestine Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Chemical Digestion in the Small Intestine · Source of enzymes that are mixed with chyme · Intestinal cells · Pancreas · Bile enters from the gall bladder Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Chemical Digestion in the Small Intestine Figure 14. 6 Copyright © 2003 Pearson Education,

Villi of the Small Intestine · Fingerlike structures formed by the mucosa · Increase

Microvilli of the Small Intestine · Small projections of the plasma membrane · Found

Structures Involved in Absorption of Nutrients · Absorptive cells · Blood capillaries · Lacteals (specialized lymphatic capillaries) Figure 14. 7 b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Absorption in the Small Intestine · Water is absorbed along the length of the small intestine · End products of digestion · Most substances are absorbed by active transport through cell membranes · Lipids are absorbed by diffusion · Substances are transported to the liver by the hepatic portal vein or lymph Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Propulsion in the Small Intestine · Peristalsis is the major means of moving food · Segmental movements · Mix chyme with digestive juices · Aid in propelling food Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Large Intestine · Larger in diameter, but shorter than the small intestine · Frames

Large Intestine Figure 14. 8 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin

Functions of the Large Intestine · Absorption of water · Eliminates indigestible food from the body as feces · Does not participate in digestion of food · Goblet cells produce mucus to act as a lubricant Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Structures of the Large Intestine · Cecum – saclike first part of the large intestine · Appendix · Accumulation of lymphatic tissue that sometimes becomes inflamed (appendicitis) · Hangs from the cecum Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Structures of the Large Intestine · Colon · Ascending · Transverse · Descending · S-shaped sigmoidal · Rectum · Anus – external body opening Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Food Breakdown and Absorption in the Large Intestine · No digestive enzymes are produced · Resident bacteria digest remaining nutrients · Produce some vitamin K and B · Release gases · Water and vitamins K and B are absorbed · Remaining materials are eliminated via feces Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Propulsion in the Large Intestine · Sluggish peristalsis · Mass movements · Slow, powerful movements · Occur three to four times per day · Presence of feces in the rectum causes a defecation reflex · Internal anal sphincter is relaxed · Defecation occurs with relaxation of the voluntary (external) anal sphincter Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Accessory Digestive Organs · Salivary glands · Teeth · Pancreas · Liver · Gall

Salivary Glands · Saliva-producing glands · Parotid glands – located anterior to ears · Submandibular glands · Sublingual glands Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Saliva · Mixture of mucus and serous fluids · Helps to form a food bolus · Contains salivary amylase to begin starch digestion · Dissolves chemicals so they can be tasted Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Teeth · The role is to masticate (chew) food · Humans have two sets of teeth · Deciduous (baby or milk) teeth · 20 teeth are fully formed by age two Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Teeth · Permanent teeth · Replace deciduous teeth beginning between the ages of 6 to 12 · A full set is 32 teeth, but some people do not have wisdom teeth Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Classification of Teeth · Incisors · Canines · Premolars · Molars Copyright © 2003

Classification of Teeth Figure 14. 9 Copyright © 2003 Pearson Education, Inc. publishing as

Regions of a Tooth · Crown – exposed part · Neck · Region in contact with the gum · Connects crown to root · Root · Attached to the bone · Root canal carrying blood vessels and nerves Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 14. 10 Slide

Pancreas · Produces a wide spectrum of digestive enzymes that break down all categories of food · Enzymes are secreted into the duodenum · Alkaline fluid introduced with enzymes neutralizes acidic chyme · Endocrine products of pancreas · Insulin · Glucagons Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Liver · Largest gland in the body · Right side of the body under the diaphragm · Four lobes suspended from the diaphragm · Connected to the gall bladder via the common hepatic duct Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Bile · Produced by cells in the liver · Composition · Bile salts · Bile pigment (mostly bilirubin from the breakdown of hemoglobin) · Cholesterol · Phospholipids · Electrolytes Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Role of the Liver in Metabolism · Several roles in digestion · Detoxifies drugs and alcohol · Degrades hormones · Produce cholesterol, blood proteins (albumin and clotting proteins) · Plays a central role in metabolism Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Gall Bladder · Sac found in hollow fossa of liver · Stores bile from the liver by way of the cystic duct · Bile is introduced into the duodenum in the presence of fatty food · Gallstones can cause blockages Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Processes of the Digestive System · Ingestion – getting food into the mouth · Propulsion – moving foods from one region of the digestive system to another Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Processes of the Digestive System · Peristalsis – alternating waves of contraction · Segmentation – moving materials back and forth to aid in mixing Figure 14. 12 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Processes of the Digestive System · Mechanical digestion · Mixing of food in the mouth by the tongue · Churning of food in the stomach · Segmentation in the small intestine Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Processes of the Digestive System · Chemical Digestion · Enzymes break down food molecules into their building blocks · Each major food group uses different enzymes · Carbohydrates - simple sugars · Proteins - amino acids · Fats - fatty acids and alcohols Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Processes of the Digestive System · Absorption · End products of digestion are absorbed in the blood or lymph · Food must enter mucosal cells and then into blood or lymph capillaries · Defecation · Elimination of indigestible substances as feces Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Processes of the Digestive System Figure 14. 11 Copyright © 2003 Pearson Education, Inc.

Control of Digestive Activity · Mostly controlled by reflexes via the parasympathetic division · Chemical and mechanical receptors are located in organ walls that trigger reflexes Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Control of Digestive Activity · Stimuli include: · Stretch of the organ · p. H of the contents · Presence of breakdown products · Reflexes include: · Activation or inhibition of glandular secretions · Smooth muscle activity Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Nutrition - Take a Class! · Nutrient – substance used by the body for growth, maintenance, and repair · Categories of nutrients · Carbohydrates: simple sugars, starches, fiber · Lipids: triglycerides, phospholipids, fatty acids · Proteins: amino acids · Vitamins · Mineral · Water Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Body Energy Balance · Energy intake = total energy output (heat + work + energy storage) · Energy intake is liberated during food oxidation · Energy output · Heat is usually about 60% · Storage energy is in the form of fat or glycogen Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Essentials of Human Anatomy & Physiology Elaine N. Marieb Seventh Edition Chapter 15 The

Functions of the Urinary System · Elimination of waste products · Nitrogenous wastes ·

Functions of the Urinary System · Regulate aspects of homeostasis · Water balance · Electrolytes · Acid-base balance in the blood · Blood pressure · Red blood cell production · Activation of vitamin D Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Organs of the Urinary system · Kidneys · Ureters · Urinary bladder · Urethra

Location of the Kidneys · Against the dorsal body wall · At the level of T 12 to L 3 · Right kidney is slightly lower · Attached to ureters, renal blood vessels, and nerves at renal hilus · Atop each kidney is an adrenal gland Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 15. 3

Coverings of the Kidneys · Renal capsule · Surrounds each kidney · Adipose capsule · Surrounds the kidney · Provides protection to the kidney · Helps keep the kidney in its correct location Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 15. 4

Regions of the Kidney · Renal cortex – outer region · Renal medulla – inside the cortex · Renal pelvis – inner collecting tube Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 15. 2 b Slide 15. 5

Kidney Structures · Medullary pyramids – triangular regions in the medulla · Renal columns – extensions of cortexlike material inward · Calyces – cupshaped structures; funnel urine towards renal pelvis Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 15. 6

Blood Flow in the Kidneys Figure 15. 2 c Copyright © 2003 Pearson Education,

Nephrons · The structural and functional units of the kidneys · Responsible forming urine · Main structures of the nephrons · Glomerulus · Renal tubule Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 15. 8

Glomerulus · A specialized capillary bed · Attached to arterioles on both sides (maintains high pressure) · Sits within a capsule Figure 15. 3 c Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Renal Tubule · Glomerular (Bowman’s) capsule · Proximal convoluted tubule · Loop of Henle · Distal convoluted tubule Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Figure 15. 3 b Slide

Types of Nephrons · Cortical nephrons · Located entirely in the cortex · Includes

Types of Nephrons · Juxtamedullary nephrons · Found at the boundary of the cortex

Peritubular Capillaries · Arise from efferent arteriole of the glomerulus · Normal, low pressure capillaries · Attached to a venule · Cling close to the renal tubule · Reabsorb (reclaim) some substances from collecting tubes Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Urine Formation Processes 1. Filtration 2. Reabsorption 3. Secretion Figure 15. 4 Copyright ©

Filtration · Nonselective passive process · Water and solutes smaller than proteins are forced through capillary walls · Blood cells cannot pass out to the capillaries · Filtrate is collected in the glomerular capsule and leaves via the renal tubule Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Reabsorption · The peritubular capillaries reabsorb several materials · Some water · Glucose · Amino acids · Ions · Some reabsorption is passive, most is active · Most reabsorption occurs in the proximal convoluted tubule Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Materials Not Reabsorbed · Nitrogenous waste products · Urea · Uric acid · Creatinine

Secretion – Reabsorption in Reverse · Some materials move from the peritubular capillaries into the renal tubules · Hydrogen and potassium ions · Creatinine · Materials left in the renal tubule move toward the ureter Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Formation of Urine Figure 15. 5 Copyright © 2003 Pearson Education, Inc. publishing as

Characteristics of Urine Used for Medical Diagnosis · Colored somewhat yellow due to the pigment urochrome (from the destruction of hemoglobin) and solutes · Sterile · Slightly aromatic · Normal p. H of around 6 (varies 4. 5 -8) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Ureters · Slender tubes attaching the kidney to the bladder · Continuous with the renal pelvis · Enter the posterior aspect of the bladder · Runs behind the peritoneum · Peristalsis aids gravity in urine transport Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Urinary Bladder · Smooth, collapsible, muscular sac · Temporarily stores urine Figure 15. 6

Urinary Bladder · Trigone – three openings · Two from the ureters · One

Urinary Bladder Wall · Three layers of smooth muscle (detrusor muscle) · Mucosa made of transitional epithelium · Walls are thick and folded in an empty bladder · Bladder can expand significantly without increasing internal pressure Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Urethra · Thin-walled tube that carries urine from the bladder to the outside of the body by peristalsis · Release of urine is controlled by two sphincters · Internal urethral sphincter (involuntary) · External urethral sphincter (voluntary) Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Urethra Gender Differences · Length · Females – 3– 4 cm (1 inch) · Males – 20 cm (8 inches) · Location · Females – along wall of the vagina · Males – through the prostate and penis Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Urethra Gender Differences · Function · Females – only carries urine · Males – carries urine and is a passageway for sperm cells Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Micturition (Voiding) · Both sphincter muscles must open to allow voiding (emptying the bladder) · Internal urethral sphincter relaxes due to stretched bladder · Activation required by nerve impulse · External urethral sphincter must be voluntarily relaxed Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Maintaining Water Balance · Normal amount of water in the human body · Young adult females – 50% · Young adult males – 60% · Babies – 75% · Old age – 45% · Water is necessary for many body functions and levels must be maintained Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Distribution of Body Fluid · Intracellular fluid (inside cells) · Extracellular fluid (outside cells) · Interstitial fluid · Blood plasma Figure 15. 7 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

The Link Between Water and Salt · Changes in electrolyte balance causes water to move from one compartment to another · Alters blood volume and blood pressure · Can impair the activity of cells Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Maintaining Water Balance · Water intake must equal water output · Sources for water intake · Ingested foods and fluids · Water produced from metabolic processes · Sources for water output · Vaporization out of the lungs · Lost in perspiration · Leaves the body in the feces · Urine production Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Maintaining Water Balance · Dilute urine is produced if water intake is excessive · Less urine (concentrated) is produced if large amounts of water are lost · Proper concentrations of various electrolytes must be present Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Regulation of Water and Electrolyte Reabsorption · Regulation is primarily by hormones · Antidiuretic hormone (ADH) prevents excessive water loss in urine · Aldosterone regulates sodium ion content of extracellular fluid · Cells in the kidneys and hypothalamus are active monitors Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Maintaining Water/Electrolyte Balance Figure 15. 9 Copyright © 2003 Pearson Education, Inc. publishing as

Maintaining Acid-Base Balance in Blood · Blood p. H must remain between 7. 35 and 7. 45 to maintain homeostasis · Alkalosis – p. H above 7. 45 · Acidosis – p. H below 7. 35 · Most ions originate as byproducts of cellular metabolism Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Maintaining Acid-Base Balance in Blood · Most acid-base balance is maintained by the kidneys · Other acid-base controlling systems · Blood buffers · Respiration Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Blood Buffers · Molecules react to prevent dramatic changes in hydrogen ion (H+) concentrations · Bind to H+ when p. H drops · Release H+ when p. H rises · Three major chemical buffer systems · Bicarbonate buffer system · Phosphate buffer system · Protein buffer system Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Developmental Aspects of the Urinary System · Functional kidneys are developed by the third month · Urinary system of a newborn · Bladder is small · Urine cannot be concentrated Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Developmental Aspects of the Urinary System · Control of the voluntary urethral sphincter does not start until age 18 months · Urinary infections are the only common problems before old age Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide

Aging and the Urinary System · There is a progressive decline in urinary function · The bladder shrinks with aging · Urinary retention is common in males Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide