E5 - The cardiovascular and nervous system of domestic birds

Question 1

Cardiovascular system

Heart

Answer 1

• Location: between 2^nd and 5^th rib
  
  • Between and in front of the lobes of the liver
  • Attached to sternum via pericardium
• Cone shaped
• Covered in fat
• Have auricles (but not always visible)
• 4 chambers
• Right atrium
  
  • ​Veins:
    
    • Vena cava cranialis dexter
    • Vena cava cranialis sinister
    • Vena cava caudalis
  • Right atrioventricular valve
    
    • ​Formed by a single muscle flap
• Left atrium:
  
  • ​Left atrioventricular valve
    
    • ​Has 3 cusps attached to chordae tendinae
  • Pulmonary trunk enters left atrium

Question 2

Cardiovacular system

Kidney

Answer 2

• Division:
  
  • Cranial division
  • Medial division
  • Caudal division
• Birds can turn off blood flow to kindey and redirect it elsewhere when needed
• Valva renalis:
  
  • ​Muscular ring around v. iliaca communis
  • ​Can regulate width - never just open or close
  • 2 valves work independently

Question 3

Cardiovascular system

Liver portal system

Answer 3

• The right and left lobes of the liver are responsible for different parts of the GI-tract
  
  • V. portalis hepatis dexter
    
    • ​Muscular stomach
    • Pancreas
    • Large intestines
  • V. portalis hepatis sinister
    
    • ​Mucosal (glandular) stomach
    • Crop
  • V. mesenterica caudalis
    
    • ​Connected to caudal end of renal portal system → kidney
    • Some blood from the GI-tract can return to the heart without passing through the liver

Question 4

Cardiovascular system

Draw the circulation system

Answer 4

• Open valve → flying mode
  
  • Vv. efferentes
• Closed valve → rest mode
  
  • Vv. afferents

Question 5

Nervous system

Brain

Answer 5

• Small
• 12 paris of cranial nerves
  
  • Same distribution as mammals (ø n. opticus
• Meninges is the same as in mammals:
  
  • Dura mater
  • Arachnoidea
  • Pia mater
• Cerebrum
  
  • ​Ø grooves or ridges
  • Sulcus sylvii
  • 2 hemispheres
• Cerebellum
  
  • ​Not as developed as in mammals
  • Vermis & grooves
  • Role: flying, moving, etc.
• Far less grey matter than in mammals

Figure: n. opticus cross over

Question 6

Nervous system

Spinal cord

Answer 6

• Ventral horn is much bulkier in birds
• Corpus gelatinosa: between S3-S6
• Canalis centralis: runs in between dorsal horns

Question 7

Nervous system

Peripheral nerves

Answer 7

• Brachial plexus
  
  • ​Dorsal & ventral plexuses
    
    • ​Plexus brachialis accessorius
• The last 2 cervical, and first 2 thoracic spinal nerves form plexus
  
  • 2 roots:
    
    • Fasciculus dorsalis (extensor muscles)
    • Fasciculus ventralis (flexor muscles)
  • Supplies the wings
• Lumbar & sysacral plexus
  
  • ​Passes through the kidney region
  • N. ischiadicus
    
    • Location:
      
      • Over a/v. ischiadica
      • Between medial and caudal kidney division
      • Between kidney and bowels
    • Clinical importance: Marek disease
      
      • ​First sign visible on n. ischiadicus (swells up)
      • Kidney disease