AP Biology Nervous Systems Brain Development

AP Biology Nervous system Central nervous system Brain Spinal cord Peripheral nervous system Somatic (voluntary) nervous system Motor pathways Sensory pathways Autonomic (involuntary) nervous system Sympathetic division Parasympathetic division  Sympathetic arousal & energy production “fight or flight”  Parasympathetic calming & back to maintenance “rest & digest”  Sympathetic arousal & energy production “fight or flight”  Parasympathetic calming & back to maintenance “rest & digest”

AP Biology Types of neurons dendrites sensory neuron cell body axon cell body interneuron cell body motor neuron dendrites “associative”

AP Biology Cephalization = Brain evolution Cnidarian nerve net Simplest nervous system no control of complex actions Simplest nervous system no control of complex actions More organization but still based on nerve nets; supports more complex movement More organization but still based on nerve nets; supports more complex movement  Cephalization = clustering of neurons in “brain” at front (anterior) end of bilaterally symmetrical animals Flatworm Platyhelminthes nerve cords associative neurons Simplest, defined central nervous system more complex muscle control Simplest, defined central nervous system more complex muscle control Echinoderm radial nerve nerve ribs  where sense organs are

AP Biology Mollusk brain giant axon brain ventral nerve cords Arthropod Further brain development ganglia = neuron clusters along CNS Further brain development ganglia = neuron clusters along CNS  increase in interneurons in brain region Earthworm central nervous system peripheral nerves More complex brains connected to all other parts of body by peripheral nerves More complex brains connected to all other parts of body by peripheral nerves More complex brains in predators most sophisticated invertebrate nervous system More complex brains in predators most sophisticated invertebrate nervous system Cephalization = Brain evolution

AP Biology Evolution of vertebrate brain Shark Frog Cat Bird Human Spinal cord Hind: Medulla oblongata Optic tectum Hind: Cerebellum Midbrain Fore: Cerebrum Olfactory tract Crocodile hindbrain  forebrain  forebrain  forebrain dominant cerebrum

AP Biology Human brain

AP Biology Functional divisions of brain  Hindbrain  evolutionary older structures of the brain  regulate essential autonomic & integrative functions  brainstem  pons  medulla oblongata  midbrain  cerebellum  thalamus, hypothalamus

AP Biology Brainstem  The “lower brain”  medulla oblongata  pons  midbrain  Functions  homeostasis  coordination of movement  conduction of impulses to higher brain centers

AP Biology Medulla oblongata & Pons  Controls autonomic homeostatic functions  heart & blood vessel activity  breathing  swallowing  vomiting  digestion  Relays information to & from higher brain centers

AP Biology Midbrain  Involved in the integration of sensory information  regulation of visual reflexes  regulation of auditory reflexes

AP Biology Reticular Formation  Sleep & wakefulness produces patterns of electrical activity in the brain  recorded as an ElectroEncephaloGram (EEG)  most dreaming during REM (rapid eye movement) sleep

AP Biology Cerebrum  Most highly evolved structure of mammalian brain  Cerebrum divided  hemispheres  left = right side of body  right = left side of body  Corpus callosum  major connection between 2 hemispheres

AP Biology Lateralization of Brain Function  Left hemisphere  language, math, logic operations, processing of serial sequences of information, visual & auditory details  detailed activities required for motor control  Right hemisphere  pattern recognition, spatial relationships, non-verbal ideation, emotional processing, parallel processing of information

AP Biology Cerebrum specialization  Regions of the cerebrum are specialized for different functions  Lobes  frontal  temporal  occipital  parietal

AP Biology

Limbic system Mediates basic emotions (fear, anger), involved in emotional bonding, establishes emotional memory Amygdala involved in recognizing emotional content of facial expression

AP Biology Simplest Nerve Circuit  Reflex, or automatic response  rapid response  automated  signal only goes to spinal cord  no higher level processing  adaptive value  essential actions  don’t need to think or make decisions about  blinking  balance  pupil dilation  startle

AP Biology Eye Blink or Pain Withdrawal Reflex Effector (muscle) Spinal cord Interneuron Gray matter White matter Motor neuron Sensory neuron Receptor in skin Stimulus

AP Biology cerebrum cerebellum spinal cord cervical nerves thoracic nerves lumbar nerves femoral nerve sciatic nerve tibial nerve Any Questions??