Thorax

Question 1

What are the cranial and caudal borders of the thorax?

Answer 1

thoracic inlet (cranial) diaphragm (caudal)

Question 2

What is a serous membrane made of?

Answer 2

mesothelium (simple squamous) with basement membrane & underlying connective tissue

Question 3

What is the function of serous membranes?

Answer 3

to secrete small volumes of serous fluid for lubrication between organs & body wall

Question 4

True/False Serous membranes contain organs

Answer 4

False only small amount of serous fluids, otherwise empty

Question 5

Characteristics of serous membranes

Answer 5

continuous thin translucent

Question 6

Name the serous membranes throughout the body

Answer 6

pleura (thoracic) (2 of them)

pericardium (around the heart)

peritoneum (abdomen)

Question 7

List the regional names of the pleura.

Answer 7

parietal membrane

visceral membrane

Question 8

What is the mediastinum?

Answer 8

the space between the pleural membranes

Question 9

Draw & label a schematic of the pleural cavities. (transverse)

Answer 9

Question 10

List the main arteries branching from the aorta.

Answer 10

Question 11

Which arteries supply the heart?

Answer 11

L&R coronary arteries

Question 12

List the arteries in the brachiocephalic trunk & what they supply.

Answer 12

L&R caroted arteries - supply the head

R subclavian artery - supplies forelimb, neck, cervicothoracic region

Question 13

What are the intercostal arteries?

Answer 13

9 paired (L&R) branches of blood vessels between the ribs

branch off the aorta

supply intercostal muscles

Question 14

Explain the progression of the subclavian artery.

Answer 14

L originates at the aorta

R originates at the brachiocephalic trunk

each has 4 branches

after branches runs into the axillary arteries

axillary arteries supply the forelimbs

Question 15

List the main veins of the thorax & where they come from.

Answer 15

cranial vena cava - head, neck, forelimbs

caudal vena cava - abdominal, pelvic, hindlimbs

azygous vein - intercostal spaces & lumbar

Question 16

What tributaries form the cranial vena cava? In order from cranial to caudal

Answer 16

external & internal jugular veins

subclavian veins

brachiocephalic veins

cranial vena cava

Question 17

How would you view the azygous vein most easily?

Answer 17

R side of mediastinum

dorsal to descending thoracic aorta

drains into cranial vena cava OR R atrium directly

Question 18

True/False

The azygous vein is paired

Answer 18

False

only one, only R side

Question 19

Which vein has a fold of mediastinal pleura?

Answer 19

caudal vena cava

Question 20

Draw & label a schematic of the main thoracic veins.

Answer 20

Question 21

Draw & label a schematic of the main thoracic arteries.

Answer 21

Question 22

List the lobes of the lungs.

Answer 22

L: cranial (has cranial & caudal parts) & caudal lobes

R: cranial, middle, diphragmatic, accessory lobes

Question 23

What is the cardiac notch?

Why is it clinically significant?

Answer 23

where the heart is not overlain with lung tissue

best place to listen to the heart

Question 24

What is the diaphragm?

Answer 24

skeletal muscle with tendonous centre

cranially-domed air tight partition between thorax & abdomen

covered in parietal pleural & parietal peritoneum

Question 25

List attachment sites of the diaphragm.

Answer 25

sternal - dorsal surface of sternum cranially to xyphoid costal - medial surface of ribs 8-13 lumbar - L&R crura at ventral region of 3&4th lumbar vertebrae

Question 26

What innervates the diaphragm?

Answer 26

L& R phrenic nerves (come from cervical spinal nerves 5-7)

Question 27

List the foramina of the diaphragm & what passes through them.

Answer 27

aortic hiatus - aorta, azygous vein, thoracic duct, sympathetic trunk oesophageal hiatus - oesophagus, dorsal & ventral vagal nerves caval foramen - caudal vena cava

Question 28

Which muscles are involved in inspiraton?

Answer 28

diaphragm scalenus serratus dorsalis cranialis external intercostal muscles internal intercostal muscles (ventral interchondral)

Question 29

Explain the process of inspiration.

Answer 29

ribs move down, out, forewards - increases transverse diameter of thoracic cavity diaphragm flattens - increases longitudinal diameter serratus dorsalis cranialis controls rib lifting increasing diameter causes increased volume, lungs expand, negative pressure draws air in

Question 30

Explain the processes of passive & active exhalation.

Answer 30

Passive: elastic recoil of lungs d/t elastic costovertebral ligmanets & durface tension in air passages Active: internal intercostal muscles, serratus dorsalis caudalis, abdominal muscles (contract to re-dome diaphragm) - reduces negative pressure

Question 31

Describe arrangement of pleura surrounding pleural cavity.

Answer 31

Question 32

What is the costo-diaphragmatic recess? What is the clinical significance?

Answer 32

.

Question 33

Draw & label a schematic of the pleural membranes (dorsal).

Answer 33

Question 34

What is the costodiaphragmatic recess?

Answer 34

region between line of pleural reflection & caudal border of lungs lungs can expand here in disease or heavy exercise but not normally

Question 35

Draw & label a schematic of the pericardium.

Answer 35

Question 36

List the components of the parietal pericardium.

Answer 36

inner, smooth, serous outer fibrous - continues to phrenicopericardial ligament & secures to diaphragm

Question 37

Draw & label a schematic of the thorax including major nerves & organs. (leave lungs out)

Answer 37