Functional Anatomy 1 - Lecture 5 - Lungs & Lymph

carbon dioxide

drives respiration

mediastinum

• central compartment of thoracic cavity

• occupied by viscera between pulmonary cavities

conduction zone

• the goal is to get gas to the areas that diffuse the gas

• also humidifies and warms the air

• includes

  • nose, pharynx, larynx

trachea

bronchioles

• smooth muscle

  • can change diameter

  • bronchoconstriction (parasympathetic)

  • bronchodilation (sympathetic)

• alveolar ducts

• alveolar sacs

  • gas exchange

transitional zone

• separates conduction system from the respiratory portion

• includes:

  • terminal bronchioles

  • respiratory bronchioles

respiratory zone

• site of gas exchange

• includes

  • alveolar ducts

  • alveolar sacs

• deoxygenated blood comes from heart via pulmonary artery

• oxygenated blood back to heart via pulmonary vein

alveoli

• thinly lined walls that allow for easy gas diffusion into the capillary bed

• all of these are interdependent of each other

  • an increase in volume of one alveolar sac increases the volume in the adjacent sac

• this is done via cross ventilation from the pores of Kohn and Lambert’s canals

blood vessel branching

lungs

• light, soft, spongy

• conical in shape, apex, base, costal surface, medial surface, hilum

right lung

• three lobes: superior, middle, inferior

• oblique and horizontal fissure

left lung

• two lobes, superior and inferior

• lingula

• cardiac notch for apex of heart

• oblique fissure

bronchopulmonary segments

root of the lungs

group of structures from the lungs to the mediastinum

hilum

the region at which vessels, nerves, etc. enter or emerge from a part/organ

bony anatomy of chest wall

• sternum

  • manubrium

  • body

  • xiphoid process

• ribs

  • costochondral

  • costosternal

  • costovertebral

respiratory muscles: ventilation

• these create a rhythmic pump to displace the chest wall

• the displacement creates a negative pressure inside of the lungs by pulling the elastic lungs “open”

• they also help the circulatory system by creating the thoracic pump to move venous blood back toward the heart

inhalation

diaphragm depresses

exhalation

diaphragm returns/elevates

diaphragm

primary inspiratory muscle

• innervated by the phrenic nerves (C3,4,5 help us breathe and stay alive)

• extremely fatigue resistant!

  • high amounts of mitochondria

  • dense/large capillary beds

  • capillary beds have a large ability to vasodilate to maximize blood flow

accessory inspiratory muscles

• external intercostals

• sternocleidomastoid

• scalenes (ant, mid, post)

• upper trapezius

• pectoralis (major, minor)

• serratus (ant, post)

• latissimus dorsi

• quadratus lumborum

diaphragm innervation

phrenic nerves (C3,4,5)

diaphragm: sternal portion

starts at xiphoid process

diaphragm: costal portion

comes from the transverse abdominal, last 6 ribs and costal cartilage

diaphragm: lumbar portion

attached to the bodies of the lumbar vertebrae to form the left and right crura

diaphragm attachments

• xiphoid process

• costal margin of thoracic wall

• ribs 11 and 12

  • L1-L3 bodies

converge to a central tendon (pericardium attaches here)

diaphragm action

contraction increases thoracic volume (inspiration)

aortic aperture of diaphragm

• aorta, thoracic duct

• posterior to diaphragm

• T12

esophageal aperture of diaphragm

• esophagus

• vagus nerve

• T10

caval aperture of diaphragm

• inferior vena cava

• T8

• right phrenic nerve

contracts, down

the diaphragm _____ as the crural and rib attachments pull the central diaphragm _____

• this creates 2 distinct different movements:

  • lateral costal expansion (bucket handle)

  • anterior/posterior upper chest wall movement (pump handle)

none!

primary muscle of exhalation

accessory muscles

• used to create even higher negative pressures and to overcome increased pulmonary and/or chest wall compliance

• this is needed with activity when greater ventilation is needed (minute ventilation) due to exercise or pathology

exhalation

passive; abdominal and internal intercostal muscles are accessory muscles used for this

• elastic recoil

  • alveolar liquid/air interface

  • elastin & collagen fibers

pleura

• secretes serous fluid

• surround each lung

• visceral (inside) and parietal (outside) parts are continuous

• pleural cavity

  • fluid to prevent rubbing of surfaces during in/exhalation

• cervical, costal, diaphragmatic, mediastinal

costodiaphragmatic recess

tracheobronchial tree innervation

• parasympathetic via CN 10 (vagus)

  • efferent function

    • bronchoconstriction

  • afferent function

    • responsible for cough reflex

• sympathetic

  • T1-T5 (pre-ganglionic) and paravertebral ganglia (post-ganglionic) to cardiopulmonary splanchnic nerves

  • adrenergic response (adrenal gland, epinephrine/norepinephrine)

  • bronchodilation

not sensitive

visceral pleura is ___ ________ to pain

innervation of the parietal pleura

1. costal: intercostal nerve

2. mediastinal: phrenic

3. diaphragmatic phrenic

innervation

sympathetic

• sympathetic trunk (T1-5) via cardiopulmonary splanchnic nerves

• bronchodilation

parasympathetics

• vagus

• bronchoconstriction

Blood Supply

blood delivered to lung tissue via bronchial arteries

• from aortic arch (left) or posterior intercostal artery (right)

venous blood drained via bronchial veins

• into azygous system

pulmonary embolism

• obstruction of pulmonary artery

• acute respiratory distress

obstructive disorders of the lung

• narrow airway-difficulty exhaling air, remains in lungs, shortness of breath

• chronic obstructive pulmonary disease, asthma, cystic fibrosis

restrictive disorders of the lung

• stiffness of lungs/chest, weak muscles - difficulty filling lungs with air, shortness of breath

• pulmonary fibrosis, obesity, ALS

Innervation and Blood Supply of diaphragm

crura of the diaphragm

• musculotendinous bundles

• arise from anterior bodies L1-L3

• L and R converge to form the median arcuate ligament

thoracic aorta

posterior intercostal vasculature

internal thoracic, musculophrenic

anterior intercostal vasculature

lymphatic system

• drainage of surplus tissue fluid

• removal of cellular debris and infection

• maintains blood volume

• lymph, drains into lymph vessels and is emptied back into blood stream

  • 1. intracellular = in cells

  • 2. intravascular = in veins

  • 3. everywhere else

increased

______ prominence of lymph nodes could mean underlying infection

right lymphatic duct

• right thorax

• right upper limb

• right head

thoracic lymphatic duct

drains lymph from the rest of the body

lymphatic system

• plays a major role in body defense mechanism

• lymph contains lymphocytes and macrophages

• lymph capillaries are found in tissues closely related to arterioles and venules

  • drain to larger lymphatic vessels that ultimately empty into subclavian veins

filtering out pathogens

lymph nodes are found in strategic locations and process lymph passing through it by

spleen

has rich blood supply, process incoming blood, engulf bacteria, viruses, worn out RBCs

thymus

near the heart shrinks with age as it is most important in infancy

• trains lymphocytes to be effective in immune system as they mature in thymus and become capable of attacking specific pathogens

tonsils

back of mouth, throat

• protect the upper GI and respiratory systems from bacteria from air and food