Module 1: NS/Lungs/Heart

OT881

The 3 planes

1. Sagittal (or median) plane
2. frontal (coronal) plane
3. transverse (axial or horizontal) plane

Sagittal plane

Right and Left halves

Frontal plane

Front and back

Transverse plane

Top and Bottom halves

Anatomical terms

superior and inferior

→ up and down

anterior and posterior

→ forward and backward

proximal and distal

→ close to midline and further from midline

medial and lateral

→ right and left

Function of the nervous system

• enables the body to react to continuous change in its internal and external environments

• Controls and integrates bodily activity

Anatomical Nervous system structure

CNS

• brain

• spinal cord

PNS

• everything else

Spinal Cord

CNS

• all the information inside the spinal cord are CNS

BUT

• As soon as that information leaves the spinal cord (out through spinal nerve to get to muscles) it becomes PNS

Sensory information will come in and synapse in the ganglia

CNS vs PNS

Somatic: Voluntary (you have to think)

Autonomic: Involuntary (smooth + cardiac muscle → heart and digestion)

1. Sympathetic (fight/flight)

2. Parasympathetic (rest + digest)

Sympathetic and parasympathetic work opposite to each other, meaning if one is regulated, the other is not

Sensory neurons

Afferent (arrives)

Motor neurons

efferent (exists)

Spinal nerves

• 31 spinal nerves

• union of posterior and anterior roots of the spinal cord

• includes sensory, motor + autonomic info

Spinal nerve sections

C1-C7

• nerves emerge above vertebrae

T1-T12

• Nerves emerge inferior

L1-L5

• cauda equina

S1-S5

• 
  

Breakfast @ 7

Lunch @ 12

Dinner @ 5

Motor and sensory pathway

Sensory information

→ coming into the back (dorsal or posterior)


Motor information

→ out through the front (ventral or anterior)

THINK:
root→ nerve→ rami

In the DOR, out the VENT

Motor neurons are:

• anterior

• ventral

• efferent

out the VENT(ral)

Motor pathway

1. starts in Ventral horn
2. out through the ventral root
3. through the spinal nerve
4. and then SPLIT into dorsal and ventral rami

Sensory neurons are:

• posterior

• dorsal

• afferent

In the DOR(sal)

Sensory pathway

ALL information entering the spinal cord will enter through the:
- Dorsal Rami
- Ventral Rami
2. travel through the spinal nerve
3. then go through the dorsal root to the Dorsal horn

Neuron overview

Thoracic pleural cavities

pleural fluid allows lungs to expand

pleura

A serous membrane forming a closed sac on the outer surface of the lung and lining the thoracic cavity

Parietal vs visceral pleura

Pleura are 2-layered sacs surrounding the lungs

- visceral = next to lung
- Parietal = next to thoracic wall

think of a pleural cavity as punching a balloon that isn’t very blown up

*fist = lung
hilum = wrist
pulmonary ligament = below wrist

Pulmonary ligament

extension of the right hilum in the inferior aspect

- double layer of pleura transitioning from visceral to parietal

Hilum

a place of transition…

* where tubes and vessels transition from the mediastinum to the lungs

contains:

• pulmonary viens

• pulmonary arteries

• primary bronchi

The left lung has lobes _ and right lung has _

Left: 2

Right: 3

Each lung has 3 surfaces:

• costal surface (against the ribs)

• Diaphragmatic surface (against the diaphragm)

• Mediastinal surface (against the mediastinum)

top of lung is the: Apex

Right lung

Landmarks:

• oblique fissure

• horizontal fissure

Lobes:

• Superior lobe

• Middle lobe

• inferior lobe

Left Lung

Landmarks

• 1 fissure: Oblique fissure

• the Lingula
  - wraps around the heart (looks like a tongue👅)

• cardiac notch: allows for heart

Lobes:

• Superior lobe

• Inferior lobe

Trachea

Made of cartilage to hold open trachea

• ‘C- shaped’ rings so the posterior side can allow for the esophagus

Basic air flow from nose to trachea

1. Air

2. nasal cavity

3. pharynx

4. larynx

5. trachea

Tracheobronchial tree

Trachea divides into primary bronchi at the carina (black star on image)

• Left = longer, more horizontal

• Right = shorter, more vertical, wider

Secondary (Lobar)

• Left = 2

• Right = 3
  
  

Tertiary (segmental)

• Bronchopulmonary segments

• no longer has cartilage - smooth muslce only to allow for airflow

• (segmental bronchus + vessels)

Respiratory/ terminal bronchiole

• smooth muscle

• no cartilage

1st structures to do gas exchange + oxygenate blood

Alveolar sacs

• site of gas exchange

• GIANT surface area for blood to be deoxygenated

Heart halves

right = thinner walls - only pumping blood to lungs

Left = thicker walls - pumping blood all around body with greater force

Heart chambers + valves

4 chambers

* 2 atria (L+R) - Superior to ventricles
* 2 ventricles (L+R)

4 valves

* 2 atrioventricular valves (atrium → ventricles)
* 2 semilunar valves (ventricles → out to body)

communicates with:

* the lungs (pulmonary)
* the body (systemic)
* itself (coronary)

2 atrioventricular (AV) valves

Atrium → ventricle

• right = tricuspid

• left = bicuspid/mitral
  * chordae tendineae prevent backflow

LAB RAT:

R = Right = T (tricuspid)

L = Left = B (bicuspid)

Vessels of the heart

• blood travelling away from the heart travels via arteries

• blood travelling to the heart comes in veins (and coronary sinus)

Blood flow

1. blood flows into right atrium
- via Sup. VC + Inf. VC
2. moves through tricuspid valve (R atrioventricular)into right ventricle
3. heads out through pulmonary semilunar valve
4. reaches the pulmonary trunk
5. which divides to become L + R pulmonary arteries (only artery to carry deox blood)
6. blood travels through pulmonary capillaries
7. back to heart through pulmonary veins
8. enters Left atrium
9. travels through the bicuspid valve (L atrioventricular)
10. to reach the left ventricle
11. exits the heart through the aortic semilunar valve
12. through the aorta to reach systemic circulation
15. arrive back at heart and enter through sup. and inf. vena cava

coronary circulation

Heart attack

R coronary artery or L coronary artery gets blocked

Where does the coronary sinus drain into?

the right atrium

(so do the anterior cardiac veins, bypassing the coronary sinus)