PPT 13 Brain Function PDF

1/5/2023 PPT 13 Areas and Organization of the Brain Brain Function 1  1/5/2023 Brain Function “Protecting your marbles” 1)Skull...

1/5/2023 PPT 13 Areas and Organization of the Brain Brain Function 1  1/5/2023 Brain Function “Protecting your marbles” 1)Skull 2)Cerebrospinal fluid (CSF) Cushions and supports against shocks Protects against infection Transports nutrients, wastes, chemicals Not the same composition as blood and ECF Formed by filtering blood – clear, pale yellow Brain Function Fig Cerebral Spinal Fluid 14.3 2  1/5/2023 Brain Function Fig 14.5 Brain Function 3)Blood-brain barrier Capillaries in brain – wrapped with connective tissue Selective barrier Fast – H2O, O2, CO2, glucose, lipid solubles Slow – Na+, K+, Cl-, and other ions Proteins, urea, creatine, toxins, antibiotics Slow diffusing is done through special channels Transport generally highly restricted 3  1/5/2023 Brain Function Meninges 3 layers that cover brain and spinal cord Meninges protect the brain from splinters in case of skull damage Order of layers (starting with outside and ending with furthest in) 1. Dura mater 2. Subdural space 3. Arachnoid mater 4. Subarachnoid space filled with CSF 5. Pia mater Brain Function Fig 14.4 4  1/5/2023 Brain Function Brain Function Fig 14.1 b 5  1/5/2023 Brain Function Fig 14.1 a Brain Function Sheep brain 6  1/5/2023 Brain Function Sheep brain Brain Function Brainstem responsible for automatic survival functions 1. Diencephalon 2. Mesencephalon 3. Pons 4. Medulla Oblongata 7  1/5/2023 Brain Function Fig 14.2 Brain Function Main Roles of Medulla Reflex centers Medullary rhythmicity center – sends impulses to breathing muscles Cardiac center – controls heart rate and force of contraction Vasomotor center – controls diameter of blood vessels – BP Other reflexes – swallowing, coughing, sneezing, hiccupping, vomiting Part of Reticular Activating System – determines level of consciousness and alertness All fiber tracts (sensory/motor) to and from brain pass through 8  1/5/2023 Brain Function Main Roles of Pons Automatic and visceral control motor control Sensory and motor cranial nerves Respiration breathing rhythm Links Cerebellum Links with brain stem, cerebrum, spinal cord Connections with rest of brain Apneustic & Pneumotaxic centers – regulates the breathing center in the medulla Fibre tracts – all ingoing and outgoing fibres pass through here Brain Function Diencephalon= Thalamus +Hypothalamus Thalamus: Ventral/medial Group – relays all sensory info (except smell) to appropriate area of cerebral cortex. Sorts and performs some interpretation Part of RAS (level of consciousness) Part of Limbic System (emotional and memory brain) 9  1/5/2023 Brain Function Memory Emotion Also involved in flight/fight – (amygdala) regulates heart rate and linking memories to danger Brain Function DO NOT MEMORIZE THIS SLIDE 10  1/5/2023 Brain Function DO NOT MEMORIZE THIS SLIDE Brain Function Cerebellum Processing center for routine movements/postures (Rapid automatic adjustments to maintain balance and equilibrium) Helps in balance Surface is very wrinkled Cerebellum can be temporarily affected by drugs and alcohol – ataxia (loss of motor coordination, dizziness, affects walking, speech etc) 11  1/5/2023 Brain Function Cerebellum Brain Function Cerebellum Main Roles 1. Coordinates and fine tunes motor movements (voluntary and subconscious)  Specifically learned movements  Cerebellum compares incoming positional information with the given commands and acts to make actions “smooth” i. Initiation commands through motor cortex to muscles ii.Stretch receptors, tendons, joint receptors activated iii.Signal goes to cortex iv.Next action is determined v.Cerebellum analyses information and sends impulses to muscles vi.Prime specific muscles for when needed Synergists Antagonists – resist movement 12  1/5/2023 Brain Function CEREBRUM Brain Function CEREBRUM: Covered by Cerebral Cortex layer (gray) This makes ridges and valleys (wrinkled) Ridges – gyri Valleys – sulci/fissures Complex analytical functions – 80% of brain mass Folding gives more surface area Pattern of the gyri is individually unique 4 main lobes Parietal Occipital Frontal Temporal 13  1/5/2023 Brain Function Cerebral Conceptual Guidelines The sensory info is received from and sent to the opposite side Eg. Motor areas on left control muscles on right Left and right hemisphere have different functions Boundaries are indistinct, hard to attach a specific function to a specific area. Hemispheric Lateralization: The 2 hemispheres are not equal Brain Function RIGHT LEFT Visual spatial skills Often called the Musical creativity dominant Ability to create mental images, creativity hemisphere Language speech Relates body to sensory environment Reading, writing Identification of familiar objects by sight, Logic taste, touch, smell, feel Decision making Facial recognition Math Analyzing the emotional content of a Understanding conversation. Also adds emotional music structure inflections Eg. “come here” Left-handed people – motor control in right hemisphere larger Right-handed people – motor control in left hemisphere larger But control for all other functions are in their same hemispheres 14  1/5/2023 Brain Function Brain Function White matter of cerebrum is mainly connecting fibers leading into other parts of the brain. The action is all with the grey matter 15  1/5/2023 Brain Function Brain Function This area is affected by Parkinson’s Disease 16  1/5/2023 Brain Function Basal Ganglia Skeletal muscle tone Subconscious muscle movements (damage gives tremors/problems with muscle tone) While you are writing a test your body functions without you noticing Learned patterns - they follow through but do not initiate movement Crossing legs – Control of muscles needed to do this, but not over the decision to do so Picking up pencil – Control over the level (shoulder) and steadiness of your arm, but not how you grab Brain Function All lobes have association areas – monitor and interpret incoming data: Stimulus goes from Thalamus to the appropriate sensory area 1. Taste - Gustatory 2. Smell - Olfactory 3. Vision - Optic 4. Touch – Primary sensory 5. Hearing - Auditory 17  1/5/2023 Brain Function Brain Function 18  1/5/2023 Brain Function Order goes: Thalamus Sensory cortex Sensory association area to be interpreted Prefrontal cortex to plan a response and verify it Motor association area if movement is needed (Either learned movement or instinctual) Brain Function All lobes have association areas – monitor and interpret incoming data from cortex: Somatic sensory association area interpret that the light touch you just felt may be a mosquito landing on your arm Visual association area interprets the signals from your receptors. You may see “c”, “a”, and “r” together but it is your Vis. Assoc. Area that recognizes this to mean “car” and all that is implied by the word. 19  1/5/2023 Brain Function Auditory association area recognizes sounds and interprets them. Eg. word recognition, garage door, front door Somatic motor association area initially to do anything motor you need to trigger each neuron in the chain to make it happen. This area deals in patterns. It interprets the signal from the cortex Eg. Playing piano. And it initiates the proper pattern of neural stimulation (involving cerebellum) to get the movements. Eg. Reading. The scanning pattern needed by your eyes. Ability to follow the lines on the page Brain Function Example situation: mosquito lands on you INITIATION OF MOVEMENT PLANNING 5 2 6 3 4 1 Sensors inform you You quickly slap it away IN OUT 20