Human Anatomy Lesson 11: Respiratory System

Respiratory System

General Functions

• Gas exchange
• Blood pH regulation
• Voice production
• Olfaction
• Innate immunity

Zones

• Conducting Zone: from nose to bronchi
• Respiratory Zone: from respiratory bronchioles to alveolar sacs

Nasal Cavity

• Divided by nasal septum
• Turbinates increase surface area for air filtration and humidification
• Pseudostratified columnar ciliated epithelium (LAAB) lines the nasal cavity

Pharynx

• Common passageway for solid foods, liquids, and air
• Divided into three sections: nasopharynx, oropharynx, and laryngopharynx

Larynx

• Made up of 9 cartilages
• Muscles in the larynx control sound production and airway opening/closing
• Glottis: opening of the airway
• True vocal cords: for sound production
• False vocal cords: prevent air from leaving the lungs

Trachea

• Made up of 16-20 C-shaped hyaline cartilages
• Posterior portion has a muscle called trachealis muscle
• Diameter changes for breathing and coughing

Bronchi

• Right primary bronchi: shorter and wider
• Left primary bronchi: longer and narrower

Lungs

• Wrapped by pleura
• Parietal pleura: outermost layer, near thoracic wall
• Visceral pleura: tightly adherent to the lungs
• Pleural cavity: between parietal and visceral pleura, contains pleural fluid

Respiratory Membrane

• Structure: alveolus, alveolar epithelium, basement membrane, capillary endothelium, and blood
• Type 1 pneumocyte: one layer thick for easy gas exchange
• Type 2 pneumocyte: produces surfactant to decrease surface tension

Respiratory Physiology

• Events in respiration: breathing, external respiration, respiratory gas transport, and internal respiration
• Lung compliance: a measure of the ease of inflation
• Respiratory volumes and capacities: tidal volume, expiratory reserve volume, residual volume, inspiratory reserve volume, inspiratory capacity, functional capacity, vital capacity, and total capacity

Pathologies

• Pleuritis: inflamed pleura

• Pleural effusion: excessive fluid in the pleural space

• Pneumothorax: air in the pleural space

• Atelectasis: collapsed lung or part of a lung

• Infant respiratory distress syndrome/hyaline membrane disease: immature lungs, lack of surfactant### Blood

• Protection against foreign substances requires Vitamins B12 and folate, Iron, and Erythropoietin (produced by the kidney)

• Blood characteristics:

  • pH: 7.35-7.45
  • Temperature: 100.4°F (38°C)
  • Blood volume: 5-6 L (6 quarts)
  • Blood makes up 8% of body weight
  • Composition: Plasma (55%), Proteins (7%), Water (91%), and Other solutes (2%)

• Formed elements: Platelets (250-400 thousand), WBC (5-9 thousand), and RBC (4.2-6.2 million)

Red Blood Cell Destruction

• Stercobilin gives color to stool
• Urobilinogen gives color to urine
• Too much RBC destruction leads to high bilirubin and jaundice (yellow skin color)

Blood Cells

• WBC (Leukocytes) functions:
  • Immune response
  • Diapedesis (emigration into surrounding tissues)
  • Ameboid motion (using pseudopodia)
  • Chemotactic response
• WBC types:
  • Neutrophils (most abundant, 60-70%)
  • Lymphocytes (20-25%)
  • Monocytes (3-8%)
  • Eosinophils (2-4%)
  • Basophils (0.5-1%)
• Granulocytes:
  • Neutrophils (multi-lobed nucleus, phagocytic)
  • Eosinophils (eosinophilic, pinkish granules, figure of 8 structure)
  • Basophils (heparin and histamine, involved in allergic reactions)

Hemostasis

• Process:
  1. Vascular spasm (smooth muscle contraction, vasoconstriction)
  2. Platelet plug formation (platelet adhesion, platelet activation, and platelet aggregation)
  3. Coagulation (fibrin formation, clotting)
• Platelet plug formation:
  • Platelet adhesion (von Willebrand factor and glycoprotein Ib-IX receptor)
  • Platelet activation (release of ADP, thromboxane A2, and adhesion)
  • Platelet aggregation (positive feedback mechanism)

Blood Disorders

• Related pathologies:
  • Sickle Cell Anemia
  • Polycythemia Vera
  • Leukemia
  • Thrombocytosis
  • Thrombocytopenia
• Hemophilias:
  • Hemophilia A (factor VIII deficiency)
  • Hemophilia B (factor IX deficiency)

Cardiovascular System

• Heart functions:
  • Generates blood pressure
  • Routes blood
  • Ensures one-way blood flow
  • Regulates blood supply
• Blood vessel functions:
  • Carries blood
  • Exchanges nutrients, waste products, and gases with tissues
  • Transports substances
  • Directs blood flow to tissues

Heart Anatomy

• Heart shape and size: blunt cone, approximately the size of a closed fist
• Heart location: thoracic cavity, surrounded by pericardial cavity
• External anatomy:
  • Right and left atria
  • Right and left ventricles
  • Coronary sulcus
  • Anterior and posterior interventricular sulcus
• Heart chambers:
  • Right atrium
  • Left atrium
  • Right ventricle
  • Left ventricle

Heart Valves

• Atrioventricular valve (AV):
  • Tricuspid valve (between right atrium and right ventricle)
  • Bicuspid valve (between left atrium and left ventricle)
• Function: allows blood to flow from atria to ventricles and prevents backflow

Pathologies

• Pericarditis (inflammation in pericardium)
• Cardiac Tamponade (fluid buildup in pericardial cavity, compressing the heart)### Heart and Blood Vessels
• The heart has four chambers: right atrium, left atrium, right ventricle, and left ventricle.
• The heart pumps blood through the circulatory system, supplying oxygen and nutrients to the body.
• The cardiac cycle consists of atrial systole, diastole, ventricular systole, and diastole.
• The cardiac conduction system includes the SA node, AV node, bundle of His, and Purkinje fibers.
• The ECG (electrocardiogram) measures the electrical activity of the heart.
• The PQ interval represents the time between the start of the P wave and the start of the QRS complex.
• The QT interval represents the time between the start of the QRS complex and the end of the T wave.

Blood Vessels

• Arteries are blood vessels that carry blood away from the heart, distributing oxygen-rich blood to the body.
• Capillaries are delicate blood vessels that allow for gas exchange between the blood and tissues.
• Veins are blood vessels that carry blood back to the heart, with valves that prevent backflow.
• The aorta is the largest artery, arising from the left ventricle and dividing into smaller arteries.
• The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.

Heart Sounds and Murmurs

• Heart sounds are caused by blood turbulence and valve closures.
• The first heart sound (S1) is caused by the closure of the AV valves, and the second heart sound (S2) is caused by the closure of the semilunar valves.
• Heart murmurs are abnormal heart sounds caused by turbulent blood flow.

Blood Pressure and Cardiac Output

• Blood pressure is the force exerted by blood on blood vessels, measured in mmHg.
• Cardiac output is the volume of blood pumped by the heart per minute.
• The formula for blood pressure is BP = CO x TPR (total peripheral resistance).
• Factors affecting cardiac output include heart rate, stroke volume, preload, afterload, and contractility.

Control of Blood Pressure

• Neural factors, such as the baroreceptors, help regulate blood pressure.
• Hormonal factors, such as the renin-angiotensin-aldosterone system, also play a role.
• The kidneys help regulate blood pressure through sodium and water balance.

Lymphatic System

• The lymphatic system is a network of vessels, organs, and tissues that defend the body against infection and disease.
• Lymphatic vessels carry lymph, a clear fluid that bathes tissues and helps remove waste and toxins.
• Lymph nodes, such as those in the neck and armpits, filter lymph and trap pathogens.
• The spleen filters the blood, removing old red blood cells and other foreign substances.

Immunity

• Innate immunity provides immediate, non-specific defense against infection.
• Adaptive immunity provides specific, long-lasting defense against infection through the action of B and T lymphocytes.
• The immune system defends against infection through mechanisms such as phagocytosis, antibody production, and complement activation.

Note: This is a summarized version of the text, focusing on key points and concepts.