Anatomy Viscera

Page 1: Introduction

  • Title: MFAC1501 Foundations Anatomy of the Viscera

  • Instructor: Patrick Chau

  • Institution: School of Biomedical Sciences, UNSW Sydney

  • Contact: patrick.chau@unsw.edu.au

Page 2: Learning Outcomes

  • Focus: Viscera of the trunk and their relation to circulation.

  • Objectives:

    1. Understand the plan and functions of the circulatory system.

    2. Describe the general organisation and functions of the cardiovascular system.

    3. Describe the general organisation and functions of the respiratory tract.

    4. Describe the general organisation and functions of the gastrointestinal tract.

    5. Describe the general organisation and functions of the genitourinary tract.

Page 3: What is Viscera?

  • Definition: Viscus (Latin)

  • Key characteristics:

    • Located in ventral body cavities

    • Composed of smooth or cardiac muscle

    • Usually hollow/tubular structures

    • Under involuntary control

    • Insensitive to pain

  • Source: Schuenke et al. (2020) Atlas of Anatomy: Internal Organs, 3rd Edition.

Page 4: Circulatory System Overview

  • Definition: Consists of cardiovascular and lymphatic systems.

  • Function: Transport of fluids and substances throughout the body.

  • Components:

    • Heart

    • Blood and lymphatic vessels

    • Blood and lymph

  • Source: Marieb et al. (2014) Human Anatomy, 7th Edition.

Page 5: Lymphatic System

  • Description: A one-way system.

  • Functions:

    • Drains excess fluid, proteins, debris, and pathogens from interstitium.

    • Leakage of ~3L/day due to Starling Principle.

    • Filtered by lymph nodes containing immune cells.

  • Drainage: Vessels drain into larger ducts, forming the right lymphatic duct or thoracic duct, returning to the venous system.

  • Source: Moore et al. (2014) Clinically Oriented Anatomy, 7th Edition.

Page 6: Cardiovascular System

  • Key Components: Heart and blood vessels.

  • Circuits:

    • Pulmonary Circuit: Gaseous exchange with lungs (from right ventricle to left atrium).

    • Systemic Circuit: Circulation to body tissues; thermoregulation (from left ventricle to right atrium).

  • Specific Circulations:

    • Liver (portal circulation)

    • Kidney (renal circulation)

  • Source: Moore et al. (2014), Marieb et al. (2014).

Page 7: Heart Location

  • Location: Occupies mediastinum in thoracic cavity, posterior to sternum, superior to diaphragm.

  • Shape: Tipped-over pyramid; apex directed anteriorly and to the left.

  • Source: Marieb et al. (2014).

Page 8: Heart Chambers

  • Features:

    • Right Atrium: Receives deoxygenated blood from the body (via superior vena cava, inferior vena cava, and coronary sinus).

    • Right Ventricle: Pumps blood into pulmonary circulation (through tricuspid valve).

    • Left Atrium: Receives oxygenated blood from lungs (via pulmonary veins).

    • Left Ventricle: Pumps blood into systemic circulation (via aorta; through bicuspid valve).

  • Source: Marieb et al. (2014).

Page 9: Heart Valves

  • Function: Prevent backflow of blood.

  • Types of Valves:

    • Atrioventricular Valves: Tricuspid and Bicuspid (mitral).

    • Semilunar Valves: Pulmonary and Aortic.

  • Source: Marieb et al. (2014).

Page 10: Blood Vessels

  • Arteries:

    • Carry blood away from the heart; located deeper than veins; have thick, muscular, elastic walls with smaller lumens.

  • Veins:

    • Carry blood towards the heart; located superficial to arteries; thinner walls, wider lumen; contains valves preventing backflow.

  • Source: Marieb et al. (2014).

Page 11: Coronary Circulation

  • Overview: Supplies blood to the heart muscle.

  • Components: RCA (Right Coronary Artery), LCA (Left Coronary Artery), Coronary Sinus.

  • Source: Marieb et al. (2014).

Page 12: Arteries of Head, Neck & Upper Limb

  • Key Arteries:

    • Brachiocephalic Trunk

    • Right and Left Common Carotid Arteries

    • Right and Left Subclavian Arteries.

  • Source: Marieb et al. (2014).

Page 13: Arteries of Abdomen, Pelvis & Lower Limb

  • Key Arteries:

    • Coeliac Trunk (to gastrointestinal viscera)

    • Superior Mesenteric Artery

    • Inferior Mesenteric Artery

    • Renal Artery (to kidneys)

    • Gonadal Artery

    • Common Iliac Artery.

  • Source: Marieb et al. (2014).

Page 14: Veins

  • Key Veins:

    • Cephalic Vein

    • Great Saphenous Vein

    • Superior Vena Cava

    • Inferior Vena Cava.

  • Classification:

    • Deep veins accompanying arteries

    • Superficial veins close to body surface (not accompanying arteries).

  • Source: Marieb et al. (2014).

Page 15: Respiratory Tract

  • Functions:

    • Ventilation (air flow)

    • Respiration (gas exchange)

    • Sound production

    • Olfaction (sense of smell).

  • Components:

    • Nasal Cavity

    • Pharynx

    • Larynx

    • Trachea

    • Bronchi

    • Lungs

    • Diaphragm.

  • Source: Marieb et al. (2014).

Page 16: Tracheobronchial Tree

  • Description:

    • Trachea extends from larynx and conducts air to/from lungs.

    • Bifurcation into right and left primary bronchi, with the right side further dividing into three secondary bronchi and the left into two.

  • Source: Netter (2019).

Page 17: Lungs

  • Occupancy: Pleural sacs in thoracic cavity.

  • Composition: Tubes and alveoli (air sacs).

  • Lobes:

    • Right Lung: 3 lobes

    • Left Lung: 2 lobes.

  • Source: Marieb et al. (2014).

Page 18: Pulmonary Circulation

  • Sequence of Blood Flow:

    1. Deoxygenated blood enters Right Atrium (RA) from SVC, IVC.

    2. Blood flows to Right Ventricle (RV) through the tricuspid valve.

    3. Into pulmonary circulation through pulmonary trunk.

    4. Gaseous exchange in lungs (CO2 for O2).

    5. Oxygenated blood enters Left Atrium (LA) via pulmonary veins.

    6. Blood flows to Left Ventricle (LV) through bicuspid valve.

    7. Into systemic circulation through aorta.

  • Source: Moore et al. (2014).

Page 19: Gastrointestinal Tract

  • Definition: Also known as the alimentary canal; spans from mouth to anus.

  • Components:

    • Oesophagus

    • Stomach

    • Small Intestine

    • Large Intestine.

  • Functions: Works with accessory organs (liver, gallbladder, pancreas) for digestion.

  • Source: Marieb et al. (2014).

Page 20: Functions of the Gastrointestinal Tract

  • Ingestion: Intake of food.

  • Propulsion: Movement of food along GIT.

  • Mechanical Breakdown: Physical preparation for chemical digestion.

  • Chemical Digestion: Breakdown of macromolecules via enzymes.

  • Absorption: Transport of nutrients into blood.

  • Excretion: Elimination of indigestible material as feces.

  • Source: Marieb et al. (2014).

Page 21: Portal Circulation

  • Pathway:

    1. Blood delivered via coeliac trunk, superior and inferior mesenteric arteries to GIT.

    2. Nutrients and toxins absorbed into capillaries.

    3. Deoxygenated but nutrient-rich blood drains into the portal vein.

    4. Portal vein enters the liver, branching into sinusoids.

    5. Liver cells filter blood of nutrients/toxins.

    6. Filtered blood enters hepatic veins and inferior vena cava, reentering circulation.

  • Source: Marieb et al. (2014).

Page 22: Summary of Portal Circulation

  1. Blood to GIT via major arteries.

  2. Nutrients absorbed into capillaries.

  3. Deoxygenated blood to portal vein.

  4. Portal vein branches within the liver.

  5. Liver cells filter blood.

  6. Filtered blood into hepatic veins to systemic circulation.

Page 23: Genitourinary Tract

  • Overview:

    • Urinary System: Filters waste, maintains fluid/electrolyte/pH balance, controls blood pressure.

    • Reproductive System: Located in pelvic cavity; produces gametes and hormones.

  • Components include kidneys, ureters, urinary bladder, and urethra.

  • Sources: Marieb et al. (2014), Schuenke et al. (2020).

Page 24: Renal Circulation

  • Description: Circulation associated with kidneys for filtering blood.

Page 25: Summary of Renal Circulation

  1. Blood to kidneys via renal arteries.

  2. Filtration occurs in nephron: water, ions, glucose, and wastes leave; large proteins remain.

  3. Resorption of essential substances into the bloodstream.

  4. Secretion of additional waste into tubes.

  5. Blood leaves via renal veins to IVC.

  6. Urine leaves kidney via ureters to urinary bladder for excretion.