Nervous System

• Occipito-vertebral artery - immediately sends an occipital branch to the posterior part of the head while the ventral branch supplies blood to the vertebral column and spinal cord 
• Subclavian artery - a large artery that supplies the shoulder region and extends to the forelimb as the brachial artery
• (2) Systemic arch → dorsal aorta → coeliaco-mesenteric artery → renal artery → spermatic or ovarian artery → adiposal artery → lumbar artery→ oviduct artery
• dorsal aorta - formed by the union of both systemic arches; runs posteriorly lying mid-dorsally just beneath the vertebral column
• coeliacomesenteric artery - a single layer artery; arises from the junction of two systemic arches; has two main branches:

  • celiac - supplies the stomach, pancreas, liver 

  anterial mesentery - supplies the spleen and intestine
• renal artery - while passing between the two kidneys, the dorsal aorta sends off 5-6 pairs of small renal arteries in a series to both the kidneys
• spermatic / ovarian artery - short arteries; they are posterior-mesenteric which arises from the posterior and dorsal aorta and sometimes from the anterior mesenteric that goes to the intestine or rectum
• • Dorsal aorta - bifurcates posteriorly into 2 common iliac artery 
  • Epigasterico-vesical artery: 
  • Epigastic - supplies the vental body wall 
  • Rectovesicular - supplies the rectum and urinary bladder 
  • Femoral artery - supplies the heath and upper thigh 

  Sciatic artery - supplies the lower leg
• Nervous System

  • Integrates all body functions
  • Transmission and processing information from the external environment or within the organism’s body
• What is the purpose of the nervous system?

  • Communicates through high speed nerve impulses
  • Receives, stores, and transmits nerve impulses
  • Control and coordinate body activities
• Afferent Division

  • Sends information to the CNS
• Efferent Division

  • Carries information away from the CNS
• Nerves

  • Pathways where these impulses are conducted are through groups of neuronal axons bundled together
• Nerve Impulses

  • Information being transmitted within the system are in this form
• PNS: Nerve, CNS: Tracts

  
  

  CNS: Nuclei, PNS: Ganglia
• Ganglia

  • Cell bodies that group together 
  • PNS
• Nuclei

  • Cell bodies cluster to form structures
  • CNS
• Cerebrum

  • Frog’s thinking center
• The Central Nervous System is composed of?

  • Brain
  • Spinal cord
• • Olfactory Bulb
  • Extends further anteriorly to form olfactory nerves (first pair of cranial nerves)
• The Peripheral Nervous System is composed of?

  • Cranial nerves
  • Spinal nerves
  • Ganglia
• PNS

  • Consists of somatic and autonomic nervous system
• Somatic Nervous System

  • Neves that go into the skin and muscle
  • Involved in conscious activities
  • In control of voluntary muscles and transmits sensory information to the CNS
• Autonomic Nervous System

  • Nerves that connect CNS to visceral organs
  • Heart
  • Stomach
  • Intestines
  • Etc
  • In control of involuntary body functions
  • 2 parts
  • Sympathetic Nervous System
  • Activates fight or flight
  • Parasympathetic Nervous System
  • Restores body to a state of calm
  • Spinal cord connects brain and PNS 
• • Sympahetic Trunk
  • Whitish nerves associated with the systemic arteries join to form the dorsal aorta
  • Part of the autonomic nervous system
• Plexus

  • Network of communicating nerves
  • 1st three spinal nerves that innervate the arm, necks, and shoulder
  • 4th, 5th, and 6th spinal nerves
  • Do not form plexus
  • 7th to 10th spinal nerves
  • Forms sciatic/lumbosacral plexus
  • Directed posteriorly and innervate hind leg
• Spinal Cord

  • Connects brain and PNS
• White matter

  • Nerve fibers carrying, ascending, and descending information
  • Outer region of the spinal cord
• Gray Matter 

  • Contains cell bodies
  • Center of the spinal cord
  • Butterfly shape
• Central Canal

  • Contains cerebrospinal fluid (CSF)
  • Cavity of the spinal cord
• Dorsal Root

  • Contains sensory fibers to transmit signals from the periphery to the dorsal root ganglion to dorsal horn
• Ventral Root

  • Contains efferent motor actions
• Dorsal Horn/Dorsal Cornua

  • Has dorsolateral extension
  • Butterfly-shaped
• Ventral Horn/Ventral Cornua

  • Ventrolateral extension
  • Motor neurons are here
  • Darkly stained
  • Star-shaped cells
• • Ventral and dorsal roots come together to form the spinal nerve
• 2 Enlargements of the spinal cord

  • Both supplying the forelimbs and hindlimbs respectively 

  1. Brachial Enlargement

  • Level of the arms and shoulder

  1. Lumbar Enlargement

  • Posterior aspect of the trunk
• Filum Terminale

  • Pointed end of the spinal cord
  • Housed within the neural canal of the urostyle
• Cauda Equina

  • Posterior end of the spinal cord
  • Roots that crowd themselves together with the filum terminale
  • Looks like a horse’s tail
• Brain

  • Elongated
  • Bilaterally symmetrical
  • Situated in the cranial cavity of the skull
• Ventricle

  • Cavities of the brain