Chapter 23 Respiratory System Respiratory System Fx Respiratory

Chapter 23 Respiratory System

Respiratory System F(x):

Respiratory Tract Conducting Portion: • Nasal cavity > pharynx > larynx > trachea > bronchi > larger bronchioles • Has respiratory mucosa • F(x): Respiratory Portion: • Smallest bronchioles and alveoli • F(x):

• Psudostratified ciliated columnar epi – Nasal cavity & superior pharynx – Trachea • Stratified squamous – Inferior pharynx • Cuboidal with cilia – Smaller bronchioles • Alveolar epithelium – Simple squamous

Defense • Filtration of debris • Mucus escalator • Alveolar macrophages-

Upper Respiratory • Pathway: nostrils (nares) > nasal vestibule (hairs) > nasal cavity (mucus) > internal nares > pharynx > glottis > larynx > trachea > bronchioles > alveoli • Nasal cavity- highly vascularized – F(x): – Divided by nasal septum • Paranasal sinuses (frontal, sphenoid, ethmoid, paired maxillary & palatine • Superior, middle, inferior meatuses- between conchae

Pharynx • Nasopharynx • Oropharynx • laryngopharynx

F(x): 9 pieces of cartilage • F(x): 1. 2. 3. 4. Lower system-Larynx thyroid cartilage (Adam’s apple)- larger in males cricoid cartilage epiglottis-door to cover glottis during swallowing – can not swallow food & breathe at same time 3 pairs of: 1. 2. 3. Arytenoid Corniculate cuneiform F(x): opening & closing of glottis

Voice Glottis: vocal folds & rima glottidis (space) • Vocal folds/cords: • Vestibular folds: • Phonation • Articulation • Amplification-

Lower system- trachea • Windpipe with cilia • Submucosa surrounded by thick layer of CT • Tracheal cartilage (c-shaped)

Lower system- Bronchial Tree • Primary bronchi branch from trachea, separated by • : where primary bronchi, BV’s, nerves, lymphatics enter lung • Primary • Secondary • Tertiary • Bronchitis • Asthma-

Lungs • R: • L: • Fissures: • Cardiac notch:

Bronchioles • Tertiary bronchus > bronchioles > terminal bronchiole > respiratory bronchiole > alveolar duct > alveolar sac > alveolus

Alveolus • Each lung ~150 mil alveoli • Simple squamous epi – Type I pneumocytes: – Type II pneumocytes: Alveolar macrophages:

Membrane for gas exchange • Alveoli <>capillary • 3 layers – Alveolar epithelium – Capillary endothelium – Basement membrane • Short distance = rapid diffusion • Pneumonia-

Respiration External • All processes involved in the exchange of O 2 & CO 2 between the body’s interstitial fluids & external environment • 3 steps: – Pulmonary ventilation– Gas diffusion– Transport of O 2 & CO 2 other tissues • Hypoxiavs Anoxia. Internal-cellular respiration – Absorbing O 2 & release of CO 2

Pulmonary Ventilation • Physical movement of air in/out respiratory tract • F(x): • Boyle’s Law • Pressure & volume inversely proportional • Gases move from

Compliance • How easily the lungs expand • Less compliance = more force to fill 1. Loss of CT = – Emphysema- 2. Loss of surfactant = 3. Loss of mobility of rib cage = – arthritis

Inhalation / Inspiration • Elastic fibers of lungs stretch • Ribs Elevate, Diaphragm contracts & moves inferiorly >

Exhalation • Elastic fibers rebound • Diaphragm moves back > • Quiet Breathing – Inhalation involves muscle contraction, exhalation is passive – Deep/Diaphragmatic- diaphragm contraction/relaxation – Costal/shallow- intercostal muscle contraction/relaxation • Forced Breathing – Exhalation involves contraction of

Respiration Volume • Tidal Volume (VT): • Residual volume: • Inspiratory Reserve Volume: • Expiratory reserve volume: Functional residual capacity: Vital capacity: Total lung capacity: • Inspiratory capacity:

Gas Laws Dalton’s Law • Atmospheric pressure: mixture of all of the gases colliding (N 2, O 2, CO 2, H 2 O) • Partial Pressure: Henry’s Law •

Pulmonary • Capillary blood P CO 2 45 mm • Alveolar blood P CO 2 40 mm • So, CO 2: • Capillary blood P O 2 40 mm • Alveolar blood P O 2 104 mm • So, O 2: Systemic • Capillary blood P CO 2 40 mm • Cell P CO 2 45 mm • So, CO 2: • Capillary blood P O 2 95 mm • Cell P O 2 40 mm • So, O 2:

Oxygen Transport • Hemoglobin molecules: 4 protein subunits with iron ions = bind O 2 molecules – 1 hemoglobin binds 4 O 2 = oxyhemoglobin (Hb. O 2) • Release of O 2 from Hb. O 2: • Carbon Monoxide Poisoning (CO) – CO wins over O 2 in fight for Hb binding > decrease O 2 to tissues > decrease ATP > cell death

Carbon Dioxide 7% Dissolves in plasma 23% Forms Hb. CO 2 carbaminohemoglobin 70% Converted to carbonic acid by RBCs • Uses carbonic anhydrase • Dissociates into H+ and bicarbonate ion HCO 3 (H+ can leave RBC & drop p. H of plasma) • Chloride Shift. Intracellular bicarbonate ions Can move out of RBC in exchange for Chloride

Control of Breathing 1. Medulla Oblongata– Dorsal respiratory group (DRG)- every cycle • Intercostals & diaphragm – Ventral respiratory group (VRG)- forced breathing • Neurons for maximal inhalation – Neurons for inhalation are opposite neurons for exhalation

2. Pons- • Apneustic: • Pneumotaxic: 3. Higher Brain Centers (cerebral cortex, limbic system, hypothalamus) • Alter activity of pneumotaxic centers

SIDS • 2 -4 months • Respiratory center is making connections with other parts of the brain and has a problem with connection > disrupts respiratory reflex • Higher in smoking homes

Respiratory Reflexes • Sensory info modifies activities of respiratory centers • Can change rate of respiration • Chemoreceptors: sensitive to P of gases &p. H in blood – Hypercapnia: • Cause: • Stimulates chemoreceptors > medulla > increase stimulation to respiratory muscles > eliminate CO 2 – Hypocapnia: • Cause:

What affects breathing? • Baroreceptors: aortic/carotid sinuses- sensitive to P – Decrease in BP = • Stretch receptors: respond to volume in lungs – Hering-Breuer Reflex- inflation & deflation during forced breathing • Irritants – Protective- sneezing, coughing – Apnea: • Glottis is forcefully closed, lungs full, blast air out glottis • Temp, Pain, Emotion- Hypothalamus, Parasympathetic vs Sympathetic

Disorders Cystic Fibrosis: • genetic disease of secretory epithelia (mutation affects the movement of chloride ions across the plasma membranes, causing a buildup of mucus) • Most common lethal genetic disease in Caucasian