Chapter 2 Part 2 Flashcards
Ventricles
- Contains cerebrospinal fluid
- Without CSF and ventricles the brain would collapse under its weight
- Cushion the brain/blows to the brain
- As we sleep, the brain flushes itself out using these mechanisms (glymphatic system)
Horizontal (axial) section
- White matter is axonal tracts covered in myelin sheath
- Connections between different areas in the brain
- Gray matter are the soma and dendrites
- Cerebral cortex (neocortex in humans)
- Thin layer (bark) on the outside
Midsaggital Section
- Corpus callosum is white matter
- The biggest commissure
- Bulges are gyri
- Spaces in between are sulci
What structures are the oldest?
The structures further back in the brain are evolutionarily older than the more forward parts
Brainstem
- medulla
- pons
- midbrai
Medulla
- Continuous with the spinal cord
- Information coming from the body to the brain comes through here and vice versa
- Breathing, heart rate, organs, reflexive behaviors (vomiting)
- Damage to it is usually fatal
- Animals like chickens use mostly the medulla rather than the rest of the brain; can survive without rest of the brain when medulla is intact
Pons
- Same circuitry as the medulla
- Basic regulatory and motor aspects
- Responsible for the sleep state of the rest of the brain (REM sleep, signals dreaming)
- Connected to the cerebellum through cerebellar peduncles
Midbrain
- Produce neurotransmitters and send them forward in the brain
- Substantia nigra
- Produces dopamine (movement) and sends it to the basal ganglia
- Parkinson’s occurs when these cells die
- Substantia nigra
- Superior colliculi
- Visual reflexes, eye movement, periphery - Inferior colliculi
- Primitive auditory system
Mike the Headless Chicken
- Farmer sliced off forebrain but kept medulla intact
- Heart kept beating and lungs kept inflating
- Survived for 18 months
- Choked to death
Cerebellum
- Has its own cortex (cerebellar cortex)
- Deep nuclei
- Balance and coordination
- Coordinating movement
- Cerebral hyperplasia (cat demonstration)
- Can learn to coordinate movements in a new way (seen in sports, dancers, curve balls)
Woman born without a cerebellum
- Walking difficulties
- Coordinate/learn movements
- Structural MRI
- Language problems as well
Purkinje Cell
- Dendrites are dense
Diencephalon Regions
- Thalamus
- Relay station
- hypothalamus
Thalamus
- Acts as a gatekeeper in processing information
- Lateral geniculate nucleus visual
- Medial geniculate auditory
Hypothalamus
- Functions
- Endocrine system (pituitary gland) releases hormones/in charge of all other glands in body/sends signals through hormones that get into your blood and circulate in your body
- Feeding, fight and flight (response to emergency situations), fucking
Parts of the Basal Ganglia and Function
- The striatum o Caudate o Putamen o Accumbens* reward behavior - Globus pallidus - Substantia niagra - Subthalamic nucleus - Movement o Selects one possible motor plan and suppresses the other ones Parkinson’s, Huntington’s
The Limbic System
- Hippocampus o memory - Amygdala o Emotional memories - Mammillary bodies o Memories
The Cerebral Cortex
- Gyri and sulci
- Thin outer layer does the most sophisticated cognitive tasks
- Bigger brain would mean bigger head which could not get through the birth canal
o Gyri and sulci to increase surface area without needing a bigger head
Ways to Classify Structures Cerebral Cortex
- gross anatomy
- cytoarchitectonics
- function
Gross Anatomy Classification
Sylvian fissure
Gyrus and sulcus
lobes
Cytoarchitectonics Classification
Arrangement of cells within different areas of the cortex
Standard human neocortex has 6 layers in it
Brodmann regions (52)
Function Classification
Sensory cortex
• Sensation, visual, auditory, gustatory, olfactory
• Starts outside the brain and flows in
• Somatosensory; temperature, pain
Motor cortex
• Movement, actions
• Starts in the brain and goes to the muscles
Association cortex
• Any cortex that is not primarily sensory or motor
• Memory, language processing, attention, problem-solving
Somatotopic maps
Prefrontal Cortex
Association areas Executive functions Plans for the future Decision making One of the last areas of the brain to fully mature; early twenties Emotional regulation
