Adapted from Ammann, Seiferle and Pelloni, 1978 … and the structures it contains.
The'medias.num'contains:''
• Nerves'• Blood'vessels'• Lymph'nodes'
• The'thymus'
• Heart'• Esophagus'
3 holes: Aortic Hiatus Esophageal Hiatus Caudal vena cava goes through the foramen (brings blood cranially).Whats the difference? The amount of movement that can occur between the walls of the structure and the hole itself. Foramen - little movability or expandibility. Esophagus needs to pass bolus of food - so it makes sense that there is more movability and expansion. Crura (2 crus) of the diaphragm - Left and Right - originate under the 1st few lumbar vertebrae and come cranially and then they fan out and become flat. Where they are bundled the structure passes through.
Mediastinum is the centre partition of the two plural cavities. 3 parts: Cranial: thymus, great vessels (brachiocephalic trunk, carotids, jugular veins).Middle: aorta, heartCaudal: aorta, caudal vena cava
Adapted from Evans and deLahunta, 2000
Phrenic Nerve
C5 C7
Nerves'
Samantha Bray
Many of these nerves are autonomic. The only obvious somatic nerve is the phrenic nerve. It supplies the diaphragm (skeletal muscle, voluntary). It has its origins from spinal nerves C5 and C7. Fracture at this point of the neck might denervate the diaphragm - NOT fatal - just a slight loss of activity.
Other nerves make up the sympathetic and parasympathetic nerves.
Cervical Thoracic Ganglion
Middle Thoracic Ganglion
Vagosympathetic Trunk
Sympathetic Trunk
Ramus Communicans
Ansa subclavia
Ganglion: collection of nerve cell bodies (perikaryon) forming a gross enlargement outside of the CNS.
Dorsal Root - where all afferents travel - bring signals into the spinal cord into the dorsal horn.
Efferent signals come out the ventral horn and to the periphery.
Spinal nerves are “mixed nerves” that come out of the intervetebral foramen. Mixed meaning it has both afferent and efferent nerves. If it was behind the 3rd thoracic vertebrae it would be called spinal nerve T3.
1 neuron from the CNS to the effector organ (e.g biceps). It is myelinate - so it is a fast system.
Composed of two neurons. The first has its origin in the CNS. The 2nd nerve is peripheral. The preganglionic fiber is myelinate (fast transmission) and the post-ganglionic fiber is not myelinated (slow transmission). Notice the length of the pre- ganglionic (short) and post ganglionic fiber (long) in the Sympathetic motor. Oppsotie in the Parasympathetic motor neurons. Stimulation of the sympathetic nervous system has a more generalized effect in the body (flight or fight). Parasympathetic stimulation is much more discreet. Neurotransmitters released are also different. Norepinephrine in the Sympathethic motor neurons and acetylcholine in the parasympathetic motor neurons.
Sympathetic: flight or fight, more generalized response, norepinephrine, adrenergic (epinephrine, dopamine, isoproterenol). It causes increased HR, increased RR, pupils dialate and lens lets you see further.
Parasympathetic: rest and digest, more specific and discrete response, cholinergic agents (nicotine, muscarine, carffeine, pilocarpine). Anticholnergic agents (atropine - a premed for anesthesia). What happens to the salivary glands - produce alot of saliva. Atropine - reduces salivation and reduces the chance of aspiration during surgery.
Parasympathetic originates at the cranial-sacral segments of the central nervous sysem. NO parasympathetic regions from the cervical, thoracic, or lumbar regions. Parasympathetic requirement for the lungs, gut, etc - has to come from nerves that have their first cell body in the brain. Motor signals come from the brain and move caudally to innervate the body.
Sympathetic nerves all come from the thoracolumbar portions of the spinal cord. NO parasympathetic nerves come from this part. Sympathetic has to get up to the brain thats why they have long axons. Brings signals from the periphery up to the brain.
1. para - oculomotor2. rostral and middle parasympathetic nuclei of medulla oblongata3. dorsal vagus nucleus4. sacral outflow5. vagus nerve6. recurrent laryngeal nerve7. parasympathetic fibers to heart and lungs8. ventral vagal drunk9. dorsal vagal trunk10 parasympathetic fibers to abdominal organs11. pelvic nerves
Parasympathetic originates at the cranial-sacral segments of the central nervous sysem. NO parasympathetic regions from the cervical, thoracic, or lumbar regions. Parasympathetic requirement for the lungs, gut, etc - has to come from nerves that have their first cell body in the brain. Motor signals come from the brain and move caudally to innervate the body.
Sympathetic nerves all come from the thoracolumbar portions of the spinal cord. NO parasympathetic nerves come from this part. Sympathetic has to get up to the brain thats why they have long axons. Brings signals from the periphery up to the brain.
1. para - oculomotor2. rostral and middle parasympathetic nuclei of medulla oblongata3. dorsal vagus nucleus4. sacral outflow5. vagus nerve6. recurrent laryngeal nerve7. parasympathetic fibers to heart and lungs8. ventral vagal drunk9. dorsal vagal trunk10 parasympathetic fibers to abdominal organs11. pelvic nerves
Study: cut the sympathetic nerves out just on 1 side - put the cat in a fridge - and cat would only have a piloerector spot on only half of its body.
Study: cut the sympathetic nerves out just on 1 side - put the cat in a fridge - and cat would only have a piloerector spot on only half of its body.
Your'dissec.on'next'lab'
22) phrenic nerve7) branches of the sympathetic trunk
22) phrenic nerve7) branches of the sympathetic trunk
The autonomic system in the thorax Ganglia
Adapted from Evans and deLahunta, 2000
Middle cervical
Cervicothoracic Sympathetic trunk ganglia
Intersection points - where there are synapses of nerves and crossing over. Called a nucleus in the CNS.
Ansa-subclavia: because loop goes around the subclavian artery and connects the sympathetic trunk to the parasympathetic trunk. Sympathetic trunk composed of branches that come from each of the thoraco-lumbar spinal nerves (called communicating branches AKA ramus commincans l communicate with spinal cord to the sympathetic trunk). Allows sympathetic nerves fiber to move craniall to supply the neck and head.
At the middle cervical the sympathetic nerves join the vagus nerve. Parasympathetic nerves come down from the head, and sympathetic signals moving craniall to the head. Vagosympathetic trunk carries both para and sympathetic fibers.
Vagus Nerve
Esophagus
Vagosympathetic trunk
Left and Right vagus nerve divides as it passes over the heart into the dorsal and ventral branch. Between the two branches are the esophagus. The two dorsal and two ventral meet on the ventral/dorsal aspect of the esophagus.
(AKA cervicothoracic ganglia)
Intersection points - where there are synapses of nerves and crossing over. Called a nucleus in the CNS.
Ansa-subclavia: because loop goes around the subclavian artery and connects the sympathetic trunk to the parasympathetic trunk. Sympathetic trunk composed of branches that come from each of the thoraco-lumbar spinal nerves (called communicating branches AKA ramus commincans l communicate with spinal cord to the sympathetic trunk). Allows sympathetic nerves fiber to move craniall to supply the neck and head.
At the middle cervical the sympathetic nerves join the vagus nerve. Parasympathetic nerves come down from the head, and sympathetic signals moving craniall to the head. Vagosympathetic trunk carries both para and sympathetic fibers.
Vagus Nerve
Esophagus
Vagosympathetic trunk
Left and Right vagus nerve divides as it passes over the heart into the dorsal and ventral branch. Between the two branches are the esophagus. The two dorsal and two ventral meet on the ventral/dorsal aspect of the esophagus.
(AKA cervicothoracic ganglia)
The autonomic system in the thorax Nerves
Adapted from Evans and deLahunta, 2000
Vagosympathetic trunk
Vertebral a & n
Sympathetic trunk
Vagus
Sympathe.c'trunk'
Aorta
Looking up into the dorsal most part of the pleural cavity/thorax.
Sympathetic Trunk - you may see enlargements (sympathetic trunk ganglia) along it
Aorta
Looking up into the dorsal most part of the pleural cavity/thorax.
Sympathetic Trunk - you may see enlargements (sympathetic trunk ganglia) along it
Caudal'Medias.num'
Aorta
Esophagus
Vagus nerve
Dorsal Vagus
Ventral Vagus
Aorta
Esophagus
Vagus nerve
Dorsal Vagus
Ventral Vagus
Sympathetic Trunk Ganglia
Thorax of a 4-month-old foal
Photo: P. F. Flood
Pulled away the dorsal border of the lung
Sympathetic trunk
Aorta
Esophagus
Dorsal Vagus
Ventral Vagus
Pulled away the dorsal border of the lung
Sympathetic trunk
Aorta
Esophagus
Dorsal Vagus
Ventral Vagus
Adapted from Evans and deLahunta, 2000
Major arteries of the thorax
Carotid
Vertebral
Left subclavian
Brachiocephalic trunk
Aorta
Violet colour: deoxygenated blood coming through the pulmonary artery (trunk) from the right ventricle into the pulmonary arteries. Same branching as the bronchial tree.
Oxygenated blood from the aorta moves blood to the body.
1st branch: coronary arteries. 1st branch after coronary arteries: brachiocephalic trunk2nd) left subclavian - in cattle and horses both the left and right subclavian arteries come off the brachiocephalic trunk. In pigs dogs and cats the only one that comes off seperately is the Left subclavian - right comes off the brachiocephalic trunk. Subclavian - axillary artery & brachial artery
Dorsal Intercostal arteries.
Violet colour: deoxygenated blood coming through the pulmonary artery (trunk) from the right ventricle into the pulmonary arteries. Same branching as the bronchial tree.
Oxygenated blood from the aorta moves blood to the body.
1st branch: coronary arteries. 1st branch after coronary arteries: brachiocephalic trunk2nd) left subclavian - in cattle and horses both the left and right subclavian arteries come off the brachiocephalic trunk. In pigs dogs and cats the only one that comes off seperately is the Left subclavian - right comes off the brachiocephalic trunk. Subclavian - axillary artery & brachial artery
Provides blood to the ventral thoracic wall and runs along the sternum (called the internal thoracic) - provides branches to the intercostals (go central to dorsal)Internal Thoracic artery??
1. Pulmonary trunk2. Aorta3. Intercostal aa. 4. L subclavian a4”. R subclavian a5. Brachiocephalic trunk6. vertebral a. 7. costocervical trunk8. L and R common carotid aa. 9. superficial cervical a. 10. axillary a. 11. internal thoracic
1. Pulmonary trunk2. Aortic arch3. Brachiocephalic trunk 4. L subclavian a5. BICAROTID trunk6. L common carotid a.
1. Pulmonary trunk2. Aorta3. Intercostal aa. 4. L subclavian a4”. R subclavian a5. Brachiocephalic trunk6. vertebral a. 7. costocervical trunk8. L and R common carotid aa. 9. superficial cervical a. 10. axillary a. 11. internal thoracic
1. Pulmonary trunk2. Aortic arch3. Brachiocephalic trunk 4. L subclavian a5. BICAROTID trunk6. L common carotid a.
Great'vessels'&'nerves'
Dog!
Brachiocephalic'trunk'
Branches'of'aor.c'arch'
Adapted from Baum, 1918
Large veins in the canine thorax
Caudal vena cava
Jugular
Cranial vena cava
Azygous vein
What'do'you'see'now?'
Cranial vena cava
Caudal vena cava
Cranial vena cava
Caudal vena cava
Thoracic'Lymphocenters'
Dorsal thoracic
(Intercostal & aortic)
Mediastinal
(cranial, middle & caudal)
Bronchial
(tracheobronchial & pulmonary)
Ventral thoracic (cranial & caudal)
drains into thoracic duct or mediastinal lymphnode
Cranial and caudal sternal lymphondes drains into mediastinal nodes
middle - at base of heartcaudal - along esophagus approching diaphragm
tracheobronchial - at tracheal bifurcationpulmonary - embedded in lung along bronchi
All lymph centres drain into the mediastinal lymphcenter.
drains into thoracic duct or mediastinal lymphnode
Cranial and caudal sternal lymphondes drains into mediastinal nodes
middle - at base of heartcaudal - along esophagus approching diaphragm
tracheobronchial - at tracheal bifurcationpulmonary - embedded in lung along bronchi
All lymph centres drain into the mediastinal lymphcenter.
