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Anatomical Model

Anatomy & Physiology: Week Eight

Chapter 23: Digestive System

Functions of the Digestive System

  • Ingest food
  • Digest it: Mechanical, Chemical
  • Absorb nutrients
  • Excrete waste

Overview of the Digestive System

  • Mouth

  • Pharynx

  • Esophagus

  • Stomach

  • Small intestine

  • Large intestine

  • Rectum, anus

  • Accessory organs

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Four Layers of the Digestive Tract

  • Mucosal layer

  • Submucosal layer

  • Muscle layer

          - Circular and longitudinal

          - Mixing, mashing action

          - Peristaltic action

          - Enteral nervous system

  • Serosal layer

  • Peritoneal membranes

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Innervation of the digestive Tract

  • Enteric nervous system (ENS)

          - Regulates gut motility and secretion

          - Modulated by autonomic nerves

 Click to label the Digestive System

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Mouth

  • Teeth: mastication

  • Tongue: swallowing

  • Salivary Glands

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Eating and Swallowing

  • Pharynx

  • Esophagus

          - Esophageal sphincters​

          - Pharyngoesophageal

          - Lower esophageal 

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Stomach Functions

  • Regulates rate of gastric emptying

  • Secretes gastric juice, including hydrochloric acid (HCl)

  • Secretes gastric hormones and intrinsic factor

  • Digests limited amount of food

  • Absorbs limited substances

Regions of the Stomach

  • Fundus

  • Body

  • Pylorus

  • Pyloric sphincter

  • Lesser curvature

  • Greater curvature

  • Rugae

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Muscles of the Stomach

  • Longitudinal

  • Oblique

  • Circular

  • Mixing and mashing chyme

  • Peristalsis

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Stomach Glands

  • Mucous cells

  • Parietal cells: HCl, Intrinsic factor

  • Chief cells: Digestive enzymes

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Small Intestine: Parts & Function

  • Parts: Duodenum, Jejunum, Ileum

  • Functions: Digests, Absorbs, Secretes hormones and digestive enzymes

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Click to review the parts of the digestive system

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Wall of Small Intestine and Absorption

  • Villi: folds increase area for absorption

​

  • Inside composed of capillaries and lacteals

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Peristalsis and Small Intestine Absorption

  • Waves of muscle contraction, relaxation

  • Pushes food from mouth toward anus

  • Peristaltic movements differ from organ to organ

Large Intestine

  • Cecum: Vermiform appendix

  • Colon

  • Ascending: Transverse, Descending,   Sigmoid

  • Rectum and anus

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Functions of the Large Intestine

  • Absorption of water and electrolytes

  • Synthesis of vitamins by intestinal bacteria

  • Temporary storage of waste

  • Elimination of waste (feces) and gas (flatus)

Peristalsis and Absorption

  • Muscle movement moves fecal material from cecum through colon

  • Constipation and diarrhea

  • Microbiota

Click to review the digestive system

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Accessory Digestive Organs

  • Liver

  • Gall Bladder

  • Pancreas

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Liver Functions

  • Synthesis of bile salts and secretion of bile

  • Synthesis of plasma proteins

  • Storage of glucose, fat-soluble vitamins

  • Detoxification

  • Main organ for drug detoxification

  • Excretion of bilirubin, cholesterol, drugs

  • Metabolism of carbohydrates, protein, fats

  • Phagocytosis (Kupffer cells, macrophages)

Hepatic Portal System

  • End products of digestion flow through portal vein to liver

  • Liver processes end products of digestion, discharging blood through hepatic veins and into inferior vena cava

Gall Bladder

  • Pear-shaped sac on the underside of the liver

          - Concentrates and stores bile

  • Attached to common bile duct by cystic duct

  • Fat in the duodenum stimulates release of the hormone cholecystokinin (CCK)

          - CCK causes gallbladder to contract, eject bile into common bile duct                 and duodenum

Pancreas

  • Located just below the stomach

  • Secretes both endocrine and exocrine substances

  • In addition to the digestive enzymes, the pancreas also secretes an alkaline juice rich in bicarbonate

  • Neutralizes the highly acidic chyme coming from the stomach into the duodenum

     Click on the pdf
      for a printable          digestive system               diagram

Chapter 24: Urinary System

Organs of Excretion

  • Kidneys
  • Skin (sweat glands)
  • Lungs
  • Intestines

Organs of the Urinary System

  • Kidneys (2)
  • Ureters (2)
  • Urinary Bladder (1)
  • Urethra (1)
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Click to review the labeling of the urinary system

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Kidneys

  • Regions

          - Renal cortex

          - Renal columns

          - Renal medulla

          - Renal pyramids

          - Renal pelvis

  • Renal capsule

  • Blood supply

          - Renal artery

          - Renal vein

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Click to review the labeling of the kidney

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Kidneys: Functions

  • Regulate blood volume and electrolytes

  • Regulate acid-base balance

  • Excrete nitrogenous waste

  • Regulate blood pressure

  • Regulate RBC production

Urine Making: The Nephron Unit

  • Functional unit of the kidney

  • Composed of two parts

          - Renal tubules​

          Renal Blood Vessels

Nephron Unit: Tubular Structures

  • Renal tubules

          - Glomerular capsule (Bowman's capsule)​

          - Loop of Henle

          _ Collecting duct

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Click for more
urinary labeling

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Click for even more
urinary labeling

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Nephron Unit: Blood Vessels

  • Renal artery

  • Afferent arteriole

  • Glomerulus

  • Efferent arteriole

  • Peritubular capillaries

  • Renal vein

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Click to review the urinary system

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Three Steps of Urine Formation

  • Glomerular filtration

  • Tubular reabsorption

  • Tubular secretion

Urine Formation: Glomerular Filtration

  • Water and dissolved solute filter across glomerulari into Bowman's capsule

  • What substances are filtered:

          - water, sodium, potassium, chloride, glucose, uric acid pass easily​

          - large blood cells and large proteins cannot fit through pores.

Urine Formation: Tubular Reabsorption

  • Returns filtrate from the tubules to the blood of peritubular capillaries

  • Most reabsorption takes place in the proximal convoluted tubule

  • The kidney chooses the type and quantity of substances it reabsorbs

What is Reabsorbed?

  • Sodium: >99%

  • Water: >99%

  • Glucose: 100%

  • Urea: 50%

  • Creatinine: 0%

Urine Formation: Tubular Secretion

  • Moves very small amounts of select substances from the peritubular capillaries into the tubules

  • Secreted substances: Potassium ions (K+), hydrogen ions (H+), uric acid, ammonium ions, and drugs

Characteristics of Urine

  • Volume: Average 1500 mL/24 hours

          - Oliguria, <400 mL/24 hours

          - Polyuria, >1500 mL/24 hours

  • pH: Average 6.0 (range, 5.0-8.0)

  • Specific gravity: Slightly heavier than water (1.001-1.035)

  • Color: Amber or straw-colored

          - Deep yellow in dehydration

          - Pale yellow with overhydration

After the NephronUnit: Then What?

Your plumbing

  • Ureters

  • Urinary bladder

  • Urethra

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     Click on the pdf
      for a printable            urinary system                    diagram

     Click to review week 8                     vocabulary words

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