IB 131 MID 3 LEC 7

Right Lung Lobes

3 lobes separated by horizontal and oblique fissures

Left Lung Lobes

2 lobes separated by a single oblique fissure

Primary Bronchi

Main left and right branches of the trachea supplying each lung

Secondary (Lobar) Bronchi

Branches of primary bronchi supplying individual lobes (3 right and 2 left)

Tertiary (Segmental) Bronchi

Branches supplying individual bronchopulmonary segments

Bronchopulmonary Segments

10 functional segments per lung containing a tertiary bronchus an artery and a vein

Trachea Epithelium

Pseudostratified ciliated columnar epithelial cells

Nasal Cavity Epithelium

Pseudostratified ciliated columnar epithelium with cilia sweeping particle-trapping mucus

Bronchiole Epithelium

Simple columnar or simple cuboidal epithelium with no cilia present

Type I Alveolar Cells

Simple squamous epithelial cells forming alveolar walls for gas exchange

Type II Alveolar Cells

Simple cuboidal cells that secrete pulmonary surfactant

Pulmonary Surfactant

Secretion reducing alveolar water surface tension to prevent collapse during exhalation

Respiratory Membrane

Barrier of simple squamous alveolar cells and capillary endothelial cells

Parietal Pleura

Serous membrane attached to the thoracic cavity wall and diaphragm

Visceral Pleura

Serous membrane directly attached to the outer surface of lung tissue

Pleural Cavity Negative Pressure

Pressure between pleurae that maintains lung expansion during thoracic volume changes

Inhalation Mechanism

Diaphragm moves downward increasing thoracic volume and decreasing internal pressure below atmospheric

Passive Exhalation Mechanism

Relaxation of diaphragm and elastic lung recoil responsible for 80 percent of exhalation work

Primary Inhalation Muscle

Diaphragm which flattens from dome shape during contraction

External Intercostal Muscles

Rib muscles that contract to pull rib cage out and up for deep inhalation

Internal Intercostal Muscles

Rib muscles that contract to compress rib cage for forced exhalation

Forced Exhalation Muscles

Internal intercostals external obliques internal obliques and transversus abdominis

Forced Inhalation Muscles

External intercostals sternocleidomastoid scalenes pectoralis minor serratus anterior and erector spinae

Phrenic Nerve

Motor nerve arising from C3 C4 C5 spinal cord levels that controls the diaphragm

C2 Spinal Cord Injury

Causes complete loss of independent breathing requiring mechanical ventilator support

Ventral Respiratory Group (VRG)

Medullary nucleus that sets the basic automatic breathing rhythm

Dorsal Respiratory Group (DRG)

Medullary center integrating chemosensory data to modify VRG rhythm

Glossopharyngeal Nerve (CN IX)

Transmits visceral O2 and CO2 chemosensory input from aortic and carotid bodies to DRG

Pneumothorax

Loss of negative pleural pressure caused by puncture resulting in a deflated lung

COPD

Chronic Obstructive Pulmonary Disease causing loss of alveolar surface area and impaired gas exchange

Emphysema

Obstructive pulmonary disease from chronic smoking causing breakdown of alveolar surface area

Cystic Fibrosis

Genetic disorder producing thick viscous mucus that disrupts airflow and traps pathogens

Bronchial Asthma

Airway inflammation causing bronchiole smooth muscle constriction and exhalation wheezing

Albuterol

Rescue inhaler bronchodilator medication that relaxes constricted bronchiole smooth muscle

Pancreas System Classification

Belongs to the digestive and endocrine systems (not lymphatic system)

Hematocrit

Percentage of total blood volume occupied by red blood cells

Erythrocytes

Scientific term for red blood cells

Thrombocytopenia

Condition characterized by an abnormally low blood platelet count