Outline flashcards for the brain

• 3 Germ Layers


  • Endoderm: epithelial linings of many organs & Gametes
  • Mesoderm: all skeletal & cardiac ms, most smooth ms., blood, lymph, marrow, vessels, dermis, kidneys/ureters/adrenal glands, dura mater
  • Ectoderm: all nervous tissue, arachnoid mater and pia mater, almost all skeletal & connective tissue, epidermis, hair/nails, skin glands, lens/cornea/internal eye ms., epithelium of pineal gland, pituitary gland and adrenal medulla
• Neurulation


  Forming neural plate, neural folds & neural groove, starting 17 days after fertilization
• Primary Brain Vesicles


  • Prosencephalon
  • Mesencephalon
  • Rhombencephalon
• Secondary Brain Vesicles


  • Telencephalon
  • Diencephalon
  • Mesencephalon
  • Metencephalon
  • Myelencephalon

  
• Brainstem


  Midbrain + Pons + Medulla Oblongata

  
• Cranium


  • Bones surrounding brain

  
• Cranial meninges


  • Dura mater
  • Arachnoid mater
  • Pia mater

  
• Dura mater


  Dense irregular CT, 2 layers - periosteal & meningeal layers > dural venous sinuses in between, Extensions: Falx cerebri, Falx cerebelli, Tentorium cerebelli

  
• Subdural space


  Between dura mater & arachnoid mater, contains ISF
• Arachnoid mater


  Thin avascular layer of loose collagen, Subarachnoid space contains cerebrospinal fluid (CSF)
• Pia mater


  Thin vascularized layer of squamous to cuboidal cells adhering to brain & SC like saranwrap
• Ventricles


  • 2 lateral ventricles
  • 3rd ventricle
  • 4th ventricle
• Choroid plexuses


  Modified capillary networks in walls of ventricles
• Ependymal cells


  Tight junctions, line capillary networks
• Functions of CSF


  • Mechanical protection: shock absorbing medium, buoys brain
  • Chemical protection: change in ionic concentration alters neuronal functioning
  • Circulation: minor exchange of nutrients and metabolic waste b/n blood and nervous tissue
• Circulation of CSF


  1. Formed in choroid plexus of lateral ventricles & 3rd ventricle

  2. Flows through cerebral aqueduct to 4th ventricle

  3. Some continues through SC via central canal but majority exits roof 4th ventricle to subarachnoid space surrounding SC

  4. Reabsorbed into dural venous sinuses via arachnoid villi and directly into the blood/lymph vessels of the pia mater
• Blood Brain Barrier


  • Tight junctions b/n endothelial cells of brain blood capillaries
  • Thick basement membrane
  • Astrocytes secrete chemicals to maintain strength of tight junctions
• What can cross the Blood Brain Barrier


  • Lipid soluble molecules: O2, CO2, steroid hormones, alcohol, barbiturates, nicotine, caffeine
  • Water
  • Glucose & ions (ions transported slowly)
  • Prevents proteins, most antibiotic drugs
• Cerebrum


  Seat of intelligence, conscious analytical thought, intelligence, personality traits, motivation, decision making
• Cerebral Cortex


  • Outer cortex: thin (2-4mm) and grey
  • Internal white matter: axons
  • Deep cerebral nuclei: grey
  • Highly convoluted: gyri/sulci (fissure if deep)

  
• Corpus callosum


  Tracts of white matter connecting hemispheres
• Functional differences between hemispheres


  • L side: language centers
  • R side: creative, artistic centers
• Cerebral Lobes


  • Frontal lobe
  • Parietal lobe
  • Temporal lobe
  • Occipital lobe
  • Insula

  
• Frontal lobe


  Deep to frontal bone, ends posteriorly at central sulcus, houses pre-central gyrus (primary motor area), Broca's speech area (control motor aspect of speech)

  
• Parietal lobe


  Underlies parietal bones, ends ant at central sulcus, houses post-central gyrus (primary (somato)sensory cortex)

  
• Temporal lobe


  Inferior to lateral sulcus, hearing & smell
• Occipital lobe


  Posterior region of hemispheres, processes incoming visual info and stores visual memories

  
• Insula


  Deep to lateral sulcus, memory and interpretation of taste (gustation)
• Types of cerebral white matter tracts


  • Association tracts
  • Commissural tracts
  • Projection tracts

  
• Basal nuclei


  3 nuclei collectively called basal nuclei (globus pallidus, putamen, & caudate nucleus), receive input from motor cortex - initiate & terminate mvmt, ms tone & unconscious mvmt of skel ms
• Structures of the Limbic System


  • Cingulate gyrus
  • Parahippocampus
  • Hippocampus
  • Dentate gyrus
  • Amygdala
  • Septal nuclei
  • Mammillary bodies

  
• Hippocampus


  Storage of STM and coverts to LTM in frontal lobe, cells can divide by mitosis
• 4 F's of the Limbic System

  • Fighting
  • Fleeing
  • Feeding
  • Fornicating (sexual behavior)
• Sensory Areas of the Cerebrum


  • Primary somatosensory area
  • Primary visual area
  • Primary auditory area
  • Primary gustatory area
  • Primary olfactory area
• Primary somatosensory area


  Parietal, post central gyrus, general somatic sensory (touch, pressure, temp, pain), sensory homunculus

  
• Primary visual area


  Posterior tip of occipital lobe, receives & processes visual information/perception

  
• Primary auditory area


  Temporal lobe, superior aspect near lateral cerebral sulcus, auditory info & memory (hippocampus)

  
• Primary gustatory area


  Base of postcentral gyrus, superior to lateral cerebral sulcus in parietal lobe (some include insular lobe), taste / gustatory perception

  
• Primary olfactory area


  Medial aspect of temporal lobe, conscious awareness of smell / olfactory perception
• Motor Areas of the Cerebrum


  • Primary motor area (cortex)
  • Broca's area (motor speech area)