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Bio104: Lecture OutlineThe Respiratory SystemL. Falkow

Martini, Chapter 21 Course Coord. 4/05

I. Introduction

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A. Components {Anatomic division}

1. Upper Respiratory System:

- nose, nasal cavity, paranasal sinuses, pharynx

2. Lower Respiratory System:

- larynx, trachea, primary bronchi, lungs (bronchi, bronchioles, alveoli)

B. Functions

1. Gas exchange

2. Conducting passageway

3. Protection of respiratory surfaces

4. Sound production

5. Sense of olfaction

C. Basic Processes

1. Pulmonary ventilation

2. External respiration - gas exchange at level of lungs

3. Internal respiration - gas exchange at level of tissues

Cellular respiration = oxidation of glucose {glycolysis, TCA cycle, electron transport}

{energy-yielding reactions}

II. Organization {Functional division}

A. Conducting division

-

[nose ---> terminal bronchioles]

B. Respiratory division

-

[respiratory bronchioles ---> alveoli]

C. Respiratory Mucosa

- lines conducting division

1. Respiratory epithelium

- PSCCE with goblet cells

- stratified squamous

- PSCCE

- cuboidal with some cilia

- simple squamous epith.

2. Lamina propria

- loose CT, mucous glands

3. Respiratory defense system

- mucus escalator:

- filtration:

- alveolar macrophages:

Cystic fibrosis (CF)

- defect on chromosome No. 7 (most common lethal inherited disease of

Caucasians)

- production of dense mucus along resp. tract

- most die before age of 30 years

III. Upper Respiratory System

A. Nose and Nasal Cavity

1. nose

2. external nares

3. vestibule

4. nasal septum

5. nasal conchae - superior, middle, inferior

nasal meatuses

6. palate

hard palate

soft palate

7. olfactory region - extends from superior nasal conchae to cribriform plate

8. internal nares

B. Nasal Mucosa

epistaxis

C. Pharynx

1. nasopharynx - superior to soft palate

2. oropharynx - soft palate ---> hyoid

3. laryngopharynx - hyoid ---> larynx & esophagus

IV. Larynx

A. Cartilages

1. thyroid cartilage -

2. cricoid cartilage -

3. epiglottis - elastic cart.

4. 3 pairs of smaller cartilages:

arytenoid

corniculate

cuneiform

B. Vocal cords

vestibular folds

- false vocal cords

- lateral location

vocal folds

- true vocal cords

- more medial location

C. Deglutition

- larynx elevates, epiglottis depresses covering the glottis

D. Coughing

- particles that touch the ventricular or vocal folds trigger coughing reflex

laryngitis = infection or inflammation of larynx

V. Trachea

A. Structure

1. Length: ~11 cm open tube

2. Histology

- Mucosa: PSCCE

- Submucosa: contains mucous glands

3. Cartilages

15-20 C-shaped cartilages

abdominal thrusts

tracheostomy - incision in anterior tracheal wall

VI. Bronchi

Trachea bifurcates -->

A. Primary bronchi (extrapulmonary)

Right primary bronchus

Left primary bronchus

Carina

B. Branching

Primary bronchi ----> intrapulmonary bronchi

Secondary bronchi (lobar) ------>

Tertiary bronchi (segmental) ---->

Bronchioles ------> terminal bronchioles

C. Changes with branching

1. cartilage

2. smooth muscle

3. epithelium

4. goblet cells

VII. Lungs

A. Location

B. Characteristics

1. apex

2. base

3. costal cartilage

4. hilus

5. root

6. cardiac notch

C. Lobes

D. Bronchopulmonary segments

E. Pleural membranes

1. parietal pleura

<pleural cavity>

2. visceral pleura

pleurisy

pneumothorax

hemothorax

VIII. Microscopic Anatomy

A. Pulmonary Lobule

terminal bronchiole

respiratory bronchiole

----> alveolar ductsplus: arteriole, venule,lymphatic vessel, CT

---> alveolar sacs

B. Alveoli

1. ~ 300 million in lungs

2. sacs are composed of 2 cell types:

- simple squamous epithelium (Type I)

- septal cells (Type II)

- also contain macrophages

3. Capillaries surrounding alveoli

4. Respiratory membrane: 2-cell layer

a. squamous epithelium

b. endothelium of capillary

5. Respiratory distress syndrome

IX. Respiratory Physiology

A. Pulmonary Ventilation

- movement of air into and out of the respiratory tract

alveolar ventilation

1. Boyle's law: inverse relationship betw. Pressure and Volume

2. Pressure and airflow

diaphragm

3. Inhalation

atm. press. =

intra-alveolar press. =

intrapleural press. =

4. Respiratory cycle = inhale + exhale

5. Respiratory muscles

Eupnea:

inspiration:

exhalation:

Forced

inspiration:

exhalation:

6. Respiratory rate:

7. Respiratory volumes

a. resting tidal volume

b. expiratory reserve volume

c. residual volume

d. inspiratory reserve volume

e. vital capacity

B. Gas Exchange at the Respiratory Membrane

1. Dalton's law and partial pressures

2. Henry's law: diffusion between liquids and gases

3. Composition of Air (atm. vs. alveolar)

4. External respiration

5. Internal respiration

C. Gas Transport

1. Oxygen

Hemoglobin - bound = 98.5%

Hb + O2 <==> HbO2

Oxygen dissolved in plasma = 1.5 %

Hemoglobin structure:

globin =

heme =

2. Carbon dioxide

- carried in blood in several forms

a. dissolved in plasma:

b. combines with globin part of Hb (carbaminohemoglobin)

c. most is transported as bicarbonate ions

CO2 + H2O <==> H2CO3 <==> H+ + HCO3-

Chloride shift:

Carbon monoxide:

3. Oxygen – Hemoglobin Saturation Curve

[Oxygen Dissociation Curve ]

Hb and pH

Hb and temperature

fetal Hb

X. Control of Respiration

A. Respiratory Centers in Medulla Oblongata

B. Apneustic & PneumotaxicCenters in the Pons

C. Respiratory Reflexes

1. Chemoreceptors

hypercapnia

hypocapnia

hypoventilation

hyperventilation

2. Baroreceptors

3. Hering-Breuer reflex

inflation reflex

deflation reflex

XI. High Altitudes

XII. Diseases of the Respiratory System

pneumonia

asthma

lung cancer

emphysema

Components of the Respiratory System

The Bronchi

Respiratory Volumes and Capacities