Lower Respiratory System

What are the 2 main components of the respiratory system?

• Upper respiratory system

• Lower respiratory system

What are the organs in the lower respiratory system?

• Bronchus

• Bronchioles #a700ff

• Lungs #ff00fe

Bronchus

• Begins at

  • Forming

• What special bronchus is present in pigs and ruminants

  • Function

• What do the principal bronchi divide into

  • Function

• What are segmental bronchi

  • Location

• Flow chart of bronchus organisation

• Walls of bronchi are supported by

Begins at: Bifurcation of trachea

• Forming: Right and left principal bronchus

What special bronchus is present in pigs and ruminants: Tracheal bronchus

• Function: Supplies the cranial lobe of the right lung

What do the principal bronchi divide into: Lobar bronchi

• Function: Each supply a lung lobe

What are segmental bronchi: Tertiary bronchi

• Location: Within lung lobes and branch from lobar bronchi

Flow chart of bronchus organisation: Trachea —> Primary bronchi —> Lobar Bronchi —> Segmental Bronchi

Walls of bronchi are supported by: Cartilaginous plates

Bronchioles #a700ff

• What structural change defines bronchiole

• Bronchioles branch into

• Bronchioles terminate in clusters of

• Where does gas exchange

What structural change defines bronchiole:

• When airways are less than 1 mm in diameter

• And lack cartilage

Bronchioles branch into:

• Terminal bronchioles

• Respiratory bronchioles

• Alveolar ducts

Bronchioles terminate in clusters of: Alveolar sacs and pulmonary alveoli

Where does gas exchange: Alveoli

The respiratory zone includes?

• Respiratory bronchioles

• Alveolar ducts

• Alveoli

Lungs #ff00fe

• Consist of

  • Which side is larger

• Location

• Normal texture

  • Allows it to

• Fresh color is

• Shaped as

• What are the parts

  • Location

• Curved lateral surface is called

• Flattened surface is called

  • Faces the

• Surface that lies against the convex surface of diaphragm is called

Consist of: Left and right lung

• Which side is larger: Right

Location: Occupies greater part of thoracic cavity

Normal texture: Sponge

• Allows it to: Be flexible and regains shape quickly after being compressed

Fresh color is: Bright pink

Shaped as: Cone

What are the parts

• Apex

  • Location: Lies in thoracic inlet

• Base

  • Location: Lies adjacent to diaphragm

• Convex lateral surface

Curved lateral surface is called: Coastal surface

Flattened surface is called: Medial surface

• Faces: Mediastinum

Surface that lies against the convex surface of diaphragm is called: Diaphragmatic surface

Lungs #ff00fe

• Label 1-6

1: Trachea

2: Left cranial lobe

3: Left caudal lobe

4: Right caudal lobe

5: Middle lobe

6: Right cranial lobe

Lungs: Surfaces

Therefore how many surfaces does the lung have?

The lungs have 3 surfaces:

• Coastal surface

• Medial surface

• Diaphragmatic surface

Lungs: Margins

• Where is the dorsal margin

• Where is the ventral margin

• Where is the basal margin

  • Continuous with

  • Positioned along

Dorsal margin: Along vertebral (spine) part of lung

• (posterior border)

Ventral margin: Along sternum (front) part of chest

• (anterior border)

Basal margin: Along the caudal (bottom) part of lung

• Continuous with: Ventral margin

• Positioned along: Diaphragm

Lungs: Hilus #ff00fe

• What is the hilus

• Location

• What is the root of the lung

What is the hilus:

• Area where:

  • Principal bronchus

  • Pulmonary artery and vein

  • Lymphatic

  • Nerves

• enter and leave the lung

Location: On the medial surface

What is the root of the lung: Bundle of the above structures that pass through the hilus

Lungs: Impressions #ff00fe

• Where is the cardiac impression located

• What are the 2 other most prominent impressions

  • Location

• On which lung can the impression of the cranial vena cava can be seen

• What is the cardiac notch

Where is the cardiac impression located: On the medial surface between the 3rd and 6th ribs

What are the 2 other most prominent impressions: Aortic and esophageal impressions

• Location: Dorsal (above) to the cardiac impression

On which lung can the impression of the cranial vena cava can be seen: Right lung

Cardiac notch: Gap between the middle and cranial lobes of the right lung where the heart makes contact with the thoracic wall

Lungs: Lobes #ff00fe

• Defined by

• In which species are the lobes not divided by deep fissues

• In which species is the cranial lobe divided into cranial and caudal parts

(look at table)

Defined by: By the presence of the lobar bronchi (secondary bronchi)

In which species are the lobes not divided by deep fissures: Horse

In which species is the cranial lobe divided into cranial and caudal parts: Ruminants

Lungs: Label Lobes #ff00fe

• Label the species 1-6

• Label the lobes a-d

Species:

• 1 = Horse

• 2 = Sheep

• 3 = Cat

• 4 = Cattle

• 5 = Pig

• 6 = Dog

Lobes:

• a = Cranial lobe

• b = Middle lob

• c = Caudal lobe

• d = Accessory lobe

Lungs: Blood Supply, Lymphatic Drainage #ff00fe

• Lung receives blood flow by

  • Function

• Blood supply comprises of what 2 vessels

Lung receives blood flow by:

• Bronchial Circulation

  • Function: Provides oxygenated blood and nutrition to the bronchi, lungs, large blood vessels, lymph nodes and visceral pleura

• Pulmonary Circulation

  • Function: Movement of blood from heart —> lungs for oxygenation then back to heart again

Blood supply comprises of what 2 vessels:

• Bronchial vessels (nutritional blood supply)

  • Bronchial artery and vein

• Pulmonary vessels (functional blood supply)

  • Pulmonary artery and vein

Lungs: Innervation #ff00fe

• What provides autonomic and sensory innervation

• Autonomic

  • Sympathetic

    • What is the effect of sympathetic stimulation on bronchial smooth muscle

    • How does sympathetic stimulation affect pulmonary vessels

    • What is the overall result of sympathetic innervation

  • Parasympathetic

    • What is the effect of parasympathetic stimulation on bronchial smooth muscle

    • What is the function of increased gland secretion during parasympathetic stimulation

    • What effect does parasympathetic innervation have on pulmonary blood flow

    • What is the overall result of parasympathetic innervation

• Sensory

  • What structures send sensory information to brainstem

  • What kind of signals are carried

What provides autonomic and sensory innervation: Pulmonary nerve plexus

Autonomic

• Sympathetic

  • What is the effect of sympathetic stimulation on bronchial smooth muscle: Causes bronchodilation (relaxes bronchial smooth muscle), increases airflow

  • How does sympathetic stimulation affect pulmonary vessels: Causes vasoconstriction which redirects blood flow

  • What is the overall result of sympathetic innervation: ↑ breathing rate and ↑ oxygen delivery

• Parasympathetic

  • What is the effect of parasympathetic stimulation on bronchial smooth muscle: Causes bronchoconstriction (contracts bronchial smooth muscle) which decreases airflow

  • What is the function of increased gland secretion during parasympathetic stimulation: Produce mucus to moisten airways and trap dust/particles

  • What effect does parasympathetic innervation have on pulmonary blood flow: Causes vasodilation which increases blood flow to lungs

  • What is the overall result of parasympathetic innervation: ↓ Breathing rate in a low-demand state

Sensory:

• What structures send sensory information to brainstem:

  • Larynx

  • Trachea

  • Bronchi

  • Vessels

  • Stretch receptors

• What kind of signals are carried: Pain and reflex signals to brainstem

Diaphragm

• Separates

• Shape

• Consist of

• Muscular periphery is divided into portions arise from

(Check labeled diagram)

Separates: Thoracic and abdominal cavities

Shape: Dome-shaped, convex

Consist of:

• Central tendon (tendinous center)

• Muscular periphery

Muscular periphery is divided into portions arise from:

• Lumbar vertebrae

• Sternum

• Caudal ribs

Diaphragm: Peripheral Muscles

• Lumbar portion

  • AKA

  • Consist of

  • Arises from

• Coastal part

  • AKA

  • Arises from

  • Attaches in what direction

• Sternal part

  • AKA

  • Arises from

  • Location

Lumbar portion:

• AKA: Pars lumbalis

• Consist of: Left and right crura

• Arises from: Ventral border of L4 and body of L3

Coastal part:

• AKA: Pars costalis

• Arises from: Inner surfaces of the ribs and costal cartilages

• Attaches in what direction: Oblique direction to the 13th through 7th rib

Sternal part:

• AKA: Pars sternalis

• Arises from: Dorsal surface of sternum

• Location: Runs dorsally to meet tendon

Diaphragm: Openings

• What are the 3 openings

  • Contains

  • Location

• Which opening doesn’t allow movement

  • Why

What are the 3 openings:

• Aortic Hiatus

  • Contains:

    • Aorta

    • Azygous vein

    • Thoracic duct (lymphatic vessels)

  • Location: Most dorsal

• Esophageal Hiatus

  • Contains:

    • Esophagus

    • Dorsal and ventral vagal nerves

    • Vessels

• Caval Foramen

  • Contains: Caudal vena cava

  • Location: Dorsal to tendinous center of diaphragm

Which opening doesn’t allow movement: Caval foramen

• Why: Tendon fused with adventitia of vessels