CH 14 PPT A&P

Chapter 14: The Respiratory System

Video Notes

Functions

• Cellular Respiration - bring in oxygen and get rid of carbon dioxide

Upper Respiratory Tract - Aid in the passage of air and moisten air before it reaches the lungs

Nasal Oral Cavity - Mouth or Nose

Pharynx - Naso, Oro, Laryngo - Esophagus -joins with digestive

Larynx - Voice Box - air passageway vocalization

Lower Tract - Branching structure

• Trachea - cartilage connects larynx to lungs, c shaped hyaline cartilage.

• Bronchi - Left & Right Primary Bronchi where the trachea divides at the 5th vertebrae. Left is wider shorter than the right.

• Lobar Bronchi - carries air to each lob of the lungs, Left has two lobes, right has three

• Segmental Bronchi -

• Subsegmental Bronchi -

Bronchioles - Smaller branches no longer contain hyaline cartilage. Branche out and end in terminal bronchioles to conducting zone and then respiratory zones in the respiratory bronchioles

Lungs - Gas exchange takes place

• Alveolar Duct - connects respiratory zone to lungs

• Alveolar Sac - contains multiple alveoli where gas exchanges takes place

• Alveoli - tiny air sacs in the lungs that facilitate the exchange of oxygen and carbon dioxide between the air and the bloodstream.

muscles used for

Diaphragm - Main muscle responsible for breathing

Inhalation - contracts lowers in the center presses the abdominal cavity

Exhalation - relaxes elastic recoil of thoaric cavity

Intercoastal Muscles - attached between our ribs, contract and pull ribs to rise

Accessory Muscles - High metabolic Demand or disfunction - Sternoclenomastiod, pectoralis, trapezoid

Pulmonary Circulation - Arteries are carrying oxygen poor blood veins carry oxygenated rich blood. Right ventricle to pulmonary trunk to pulmonary arteries into bronchi and into the capillaries where gas exchange takes place. Then to venules to veins back into the left atrium of the heart, completing the cycle of oxygenated blood returning to the systemic circulation. Low pressure System systolic pressure of 20-25

Bronchial Circulation - High Pressure system, provide blood and oxygen to the lungs itself. Some deoxygenated blood to the left side of the heart.

14.1 Overview of the Respiratory System

• Major Function: Gas exchange within the body.

• Works in conjunction with the cardiovascular system through:

  • Pulmonary Ventilation: Breathing involving both inhalation (inspiration) and exhalation (expiration).

  • External Respiration: Exchange of oxygen and carbon dioxide between air in the lungs and blood.

  • Internal Respiration: Gas exchange between blood and tissue fluid.

  • Transport of Gases: Blood effectively transports gases between the lungs and tissues.

  • Ph Balance

14.2 Purpose of Respiration

• Goal: To provide oxygen for cellular respiration and eliminate carbon dioxide waste.

• Cellular Respiration: Produces ATP; thus, cells require a constant oxygen supply to function.

14.3 The Respiratory Tract

Upper Respiratory Tract

• Nasal Cavity: Filters, warms, and moistens air.

• Pharynx: Crosses pathway for air and food.

• Glottis: Space between the vocal cords, leading to the larynx.

• Larynx (Voice Box): Produces sound; covered by the epiglottis when swallowing.

Lower Respiratory Tract

• Trachea: Windpipe directing air to the bronchi.

• Bronchus: Main passageway into lungs.

• Bronchioles: Smaller air passages leading to alveoli.

• Lungs: Contains alveoli, where gas exchange occurs.

• Diaphragm: Skeletal muscle essential for breathing.

14.4 Mucosal Protection

• Nasal Hairs, Cilia, Mucus: Cleanse inhaled air.

• Lysozyme: Enzyme in mucus that kills bacteria.

• Mucociliary Escalator: Cilia push mucus toward the throat for swallowing.

• Warming & Moistening of Air: Achieved by blood vessels lining airways.

14.5 Components of the Nose

• Nasal Structure: Contains two cavities lined with mucous membrane and nasal conchae (ridges) to increase surface area.

• Olfactory Epithelium: Contains receptors for smell.

• Paranasal Sinuses - Cavities inside the skull. Sinusitis

14.6 The Path of Air

• Airway Pathway: Follows the nasal cavities, pharynx, larynx, trachea, bronchial tree to alveoli for air exchange.

14.7 The Pharynx

• Connects nasal and oral cavities to the larynx, containing three parts: nasopharynx, oropharynx, and laryngopharynx.

14.8 The Larynx

• Functions as the air passageway disallowing food intake, containing vocal cords that produce sound; pitch regulated by cord tension.

• Glottis - space between the vocal cords that plays a crucial role in phonation and breathing.

• Epiglottis - the flap of tissue that covers the glottis during swallowing, preventing food and liquid from entering the trachea.

14.9 The Trachea

• Connects larynx to primary bronchi; lined by ciliated columnar epithelium facilitating mucus movement (mucociliary escalator).

14.10 The Bronchial Tree

• Bronchial Structure: Starts at primary bronchi, branching to secondary and tertiary bronchi, leading to bronchioles with no cartilage.

14.11 The Lungs

• Left Lung: Upper Lobe, Lower Lobe

• Right Lung: Upper Lobe, Middle Lobe, Lower Lobe

• Cone-shaped with apex at the top; divided into lobules served by bronchi and pulmonary arteries.

• Surfactant: Substance preventing alveoli collapse, producing a thin layer for gas exchange.

• Alveoli Sacs - simple squamous epithelium

14.12 Gas Exchange Mechanism

• Respiratory Membrane: Composed of alveolar and capillary epithelium; facilitates rapid gas exchange.

14.13 Mechanism of Breathing

Ventilation Overview

• Ventilation: Air movement in and out of lungs; relies on pressure changes within thoracic cavity. Intrapleural Pressure -

• Spirometer - records volume of air exchanged during breathing cycles, providing valuable data for assessing lung function and capacity.

• Spirogram - shows the measurements recorded by a spirometer

• Residual Volume - the amount of air remaining in the lungs after a maximal exhalation, which cannot be voluntarily expelled.

• Control - primary respiratory center in medulla, Phrenic nerve and intercoastal muscles

Inspiration

• Active process involving diaphragm and external intercostal muscle contraction leading to decreased alveolar pressure, allowing air inflow.

Expiration

• Typically passive; diaphragm relaxes, rib cage descends, lung volume decreases, leading to increased pressure and air expulsion.

Erector Spinae Muscle : A group of muscles located along the spine that help maintain posture and assist with the extension and lateral flexion of the vertebral column.

Pectoralis Minor : A thin, flat muscle located beneath the pectoralis major, it plays a role in stabilizing the scapula and can assist in forced expiration by pulling the ribs downward.

Scalene muscles: A group of three muscles located on the lateral sides of the neck, they assist in elevating the first and second ribs during forced inhalation and contribute to neck flexion.

Sternocleidomastoid : A prominent muscle in the neck that plays a crucial role in rotating and flexing the head, as well as assisting in forced inhalation by elevating the sternum.

14.14 Respiratory Volumes

• Tidal Volume: ~500 mL, air in/out per normal breath.

• Vital Capacity: Maximum inhalation and exhalation capacity, factoring inspiratory and expiratory reserve volumes.

• Residual Volume: Air left post-expiration; ~1,000 mL.

14.15 Control of Ventilation

• Primary Control: Medulla oblongata regulates breathing rhythm; interactions occur with pons and nerve signaling.

• Nervous Input: Influences depth/rate of breathing through various brain regions.

• Chemical Input - Chemoreceptors in the carotid and aortic bodies detect changes in blood pH, carbon dioxide, and oxygen levels, providing feedback to the medulla and pons to adjust ventilation accordingly.

14.16 Gas Exchange & Transport

External Respiration -

Gas Transport -

Internal Respiration -

• Oxygen Transport: Primarily by hemoglobin; oxygen binds to form oxyhemoglobin.

• Carbon Dioxide Transport: Dissolved in plasma, bound to hemoglobin, or as bicarbonate ions. HCO3

• Chloride Shift -

14.17 Respiratory Disorders

• 12-18 breathes a minute

• Hyperpnea - higher than normal breathing

• Hypoventilation - Increase CO2 acidosis low ph slower than normal breathing, which can lead to an increase in carbon dioxide levels in the blood.

• Hyperventilation - decreases CO2 alkalosis high ph.

Upper Respiratory Tract Infections

• Various infections from nasal cavities extending to the sinuses; include strep throat - bacterial infection

• sinusitis - inflammation of the sinuses

• Ottis Media - Bacterial infection of the middle ear, often spread from the pharynx. Seen in children

• Tonsillitis - Become inflames Tonsillectomy - removal of tonsils

• Laryngitis - Cause by viruses and by smokers hoarsness of voice

Lower Respiratory Tract Disorders

• Bronchitis: Primary/secondary bronchial infection. Preceded by a viral upper respiratory infection

• Pneumonia: Viral or bacterial Infection filling alveoli with thick fluid. May be localized in specific lobules of lungs

• Tuberculosis: Infection developing tubercles in lung tissue.

• Emphazema: A condition characterized by the destruction of the alveoli, leading to reduced surface area for gas exchange and difficulty in breathing.

• COPD (Chronic Obstructive Pulmonary Disease): Includes chronic bronchitis and emphysema, significantly affecting airflow.

• Respiratory distress Syndrome - premature infants who lack surfactant

• Restrictive Or Obstructive Disorders

• Asthma

• Lung Cancer - Pneumonectomy removal of lobe or entire lung. Smoking leading cause of lung cancer

14.18 Aging Effects

• Aging results in decreased respiratory efficiency, thickened respiratory membranes, and higher susceptibility to respiratory diseases.Part of the endocrine system as well, turns Angiotensin 1 to angiotensin 2