Chapter 24: Ribs/Thoracic Cage & Muscles of respiration

Chemoreceptor reflexes of Respiration

-Respond to changes in partial pressures of Carbon dioxide/Oxygen -Respond to physical injury/irritation

Protective reflexes of Respiration

-Respond to physical injury or irritation

Respiratory rhythmicity center

Sets the respiratory pace

Respiratory Movements

(2) types: 1. Eupnea 2. Hyperpnea

Respiratory centers of the brain

(3) pairs of nuclei in the ons/medulla oblongata that regulate respiratory muscles 1. Respiratory rhythmicity center 2. Apneustic Center 3. Pneumotaxic Center

Prior to birth

-Pulmonary arterial resistance is high (Pulmonary vessels are collapsed) -Rib cage is compressed -Lungs and passageways contain no air but DO contain small amounts of fluid

Eupnea

-Quiet Breathing -Diaphragmatic breathing and/or Costal Breathing -During pregnancy, because the uterus pushes upward on the diaphragm, women typically use costal breathing

Mechanoreceptor reflexes of Respiration

-Respond to changes in lung volume or changes in blood pressure

Ribs 11-12

-"Floating Ribs" -No neck -Only one facet for articulation with corresponding vertebra

At birth

-Air enters lungs and forces fluid out -Foramen Ovale/Ductus arteriosus close

Posterior articulation of the ribs

-All (12) ribs articulate posteriorly with the vertebrae of the spine forming (2) joints 1. Costotransverse joints 2. Costovertebral joints

Aging and the Respiratory System

-Becomes less efficient -Elastic tissue beings to deteriorate (lungs cannot expand/constrict as much) -Movement of ribs = Restricted due to arthritis -Some degree of emphysema hinders breathing -Roughly 1sq. foot of respiratory membrane is lost each year after age 30 (People<30 take in 2x the O2 of someone who is >80)

Costal Cartilage

-Cartilage at the anterior point of termination of the ribs

Adult Respiratory Distress syndrome (ARDS)

-Condition resulting from inadequate surfactant -Characterized by collapse of the alveoli/inability to maintain gaseous exchange in the lungs -Also called "Hyaline membrane disease of the newborn" which is common in preterm/premature births (because surfactant develops in the last trimester)

Breathing (ventilation)

-Consists of air going in and out of lungs -About .5L of water is lost through this. -Takes in 13 pints of air/min

Neck of Typical Rib

-Contains no bony prominences -Connects the head with the body, at this point, there is a roughened tubercle -Rough tubercle serves as a facet for articulation with the transverse process of the corresponding vertebrae

Dyspnea

-Difficulty/labored breathing -Indicative of serious disease of the lungs/hear

Body/Shaft of Typical Rib

-Flat & Curved -Internal surface has a groove for the neurovascular supply of the thorax. Groove protects the vessels/nerves from damage

Hyperpnea

-Forced Breathing -Generally requires the use of accessory breathing muscles

Rib 10

-Only one facet for articulation with its numerically corresponding vertebrae

Costovertebral joints

-Point of articulation between the head of the rib, the superior costal facet of the corresponding vertebrae and the inferior costal facet of the vertebrae above

Costotransverse joints

-Point of articulation between the tubercle of the rib and the transverse costal facet of the corresponding vertebrae

Ribs

-Set of 12 bone which from the protective 'cage' of the thorax -Articulate with the vertebral column posteriorly, and terminate anteriorly as cartilage -Protect internal thoracic organs -Permit lung inflation (breathing) via chest expansion -(2) types: 1. Typical ribs 2. Atypical Ribs

Rib 1

-Shorter/wider than others -Has (1) facet on its head for articulation with its corresponding vertebrae (No thoracic vertebrae above) -Superior surface is marked by (2) grooves which make way for subclavian vessels

Rib 2

-Thinner/longer than rib 1 -(2) articular facets on the head (normal) -Roughed area on its upper surface where the serrates anterior muscle attaches

Anterior articulation of the ribs

-Vary depending on the ribs: Ribs 1-7: Attach independently to the sternum Ribs 8-10: Attach to the costal cartilages superior to them Ribs 11-12: Do not have an anterior attachment. They end in the abdominal musculature --> Floating ribs

Head of Typical Rib

-Wedge shaped -(2) articular facets separated by a wedge of bone --> One facet articulates with the numerally corresponding vertebra --> Other fact articulates with the vertebrae above

Frail Chest

-When more than one rib is fractured, the affected area is no long under control of the thoracic muscles -Displays a paradoxical movement during lung inflation/deflation

(4) Respiration processes

1. Breathing (ventilation) 2. External Respiration 3. Internal Respiration 4. Cellular Respiration **We breathe 15-50x per min**

Diaphragm

1. Contracts (lowers) during inhalation 2. Relaxes (raises) during exhalation

Inspiratory muscles

1. Diaphragm 2. External intercostal muscles

Muscles involved in pulmonary ventilation (breathing)

1. Diaphragm 2. External intercostals 3. Internal intercostals

Accessory respiratory muscles

1. Inspiration: Sternocleidomastoid/Serratus anterior/Pectoralis minor/Scalene muscles 2. Expiration: Transverses thoracis/oblique & rectus abdominis/Intercostal muscles

Reflexes involved in Respiration

1. Mechanoreceptor reflexes 2. Chemoreceptor reflexes 3. Protective reflexes

Apneustic Center/Pneumotaxic Center

Adjust the respiratory pace

Emphysema

Chronic respiratory disorder resulting from destruction of respiratory exchange surfaces/alveoli

Rib articulation

Consists of (2) types: 1. Posterior articulation 2. Anterior articulation Majority of ribs have both types

Thoracic Cage

Consists of: 1. Ribs 2. Costal Cartilage 3. Sternum

Muscles of Respiration

Consists of: 1. Inspiratory muscles 2. Expiratory muscles 3. Accessory Respiratory muscles

Internal intercostals

Depress the ribs to aid in exhalation

External Intercostals

Elevates the ribs to aid in inhalation

External Respiration

Gas exchange between air & blood

Internal Respiration

Gas exchange between blood & tissues

Typical Ribs

Generalized structure -Consist of a head/neck/body

Bronchitis

Inflammation of bronchial lining

Tachypnea

Rapid shallow breathing due to imbalance b/w CO2 & O2

Atypical Ribs

Ribs 1, 2, 10-12

Cellular Respiration

The use of Oxygen in the production of ATP and excretion of Carbon dioxide as waste

Expiratory muscles

Usually not needed due to elastic recoil of lungs and thoracic cavity