The Central Nervous system The Body’s Processing Centre

Work your Brain Complete the back side of the brain teasers from last week’s class Can you decipher #31?!? Stroop test Test your short-term memory at https://www.psychologistworld.com/memory/test2.php Watch part of Bozeman science podcast at: https://www.youtube.com/watch?v=UabDiuTtU0M (to 3min45sec)

Case Study: Phineas Gage The strange but true story of a 25-year old railway construction foreman September 1848 Textbook p. 432

The Nervous System Split into 2 parts: 1. Central nervous system The structural & functional core of the nervous system Is the processing centre for the body Receives info from sensory neurons Evaluates the information Initiaties a response by sending signals to muscles and glands via the PNS Composed of the brain and spinal cord 2. Peripheral nervous system Composed of sensory (receptor) and motor (effector) pathways

Body Worlds Exhibit

Differences in Complexity

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

Nervous system Central nervous system Peripheral nervous system Spinal cord Sensory pathways Motor pathways Brain Somatic (voluntary) system Autonomic (involuntary) system Sympathetic division Parasympathetic division

Types of neurons sensory neuron interneuron motor neuron cell body axon interneuron dendrites dendrites cell body motor neuron

The Crucial Organ: The Brain Processes and interprets incoming stimuli and information Relays a message or causes a response Directs all bodily functions Divided into lobes

Did you know? The average brain weighs about 3 lbs The brain is the fattest organ in the body Your brain is about 75% water There are about 100 billion neurons in the brain alone Most of these neurons are interneurons There are anywhere from 1,000 to 10,000 synapses for each of these interneurons The brain consumes about 20% of the oxygen and food contained within blood The cerebrum composes about 85% of the whole human brain

The Brain’s Protection Despite its central importance, the brain is super fragile and has a Jello-like consistency Implications for concussions and chronic traumatic encephalopathy (CTE) Skull forms a bony, protective armour around the brain Meninges are 3 layers (dura, arachnoid, pia) of tough, elastic tissue that encase the brain and spinal cord Cerebrospinal fluid (CSF) is a dense, clear liquid that acts as a shock absorber Located between arachnoid & pia mater layers

3 Main Divisions of The Brain

Hindbrain, Midbrain, ForeBrain Hindbrain  cerebellum, brainstem (medulla oblongata & pons) Responsible for coordination and movement Midbrain Processes sensory input Forebrain  cerebrum, thalamus, hypothalamus Regulates thought, learning, and emotion

Major Brain Structures Cerebrum Thalamus Hypothalamus Cerebellum Brain stem II III IV V

Cerebrum Most highly evolved structure of mammalian brain Composed of 2 hemispheres left  controls right side of body right  controls left side of body Corpus callosum is the major connection between the 2 hemispheres Folds & grooves greatly increase surface area and ability to do work Divided into lobes

Lateralization of Brain Function

Cerebral Lobes Regions of the cerebrum are specialized for different functions 4 Lobes Frontal  front Temporal  side Parietal  top back half Occipital  back bottom portion

Somatosensory Cortex in the Parietal Lobe The main sensory receptive area for the skin

Brain Anatomy Cerebrum Corpus callosum Cerebellum Pons Medulla http://www.daviddarling.info/images/cerebrum.jpg

Lateral View of the Cerebrum

Cerebral Lobes Carry out sensory and voluntary motor functions Responsible for higher mental processing 4 lobes Use your textbook or online sources to find out what each lobe is responsible for Make your own note

Function of Each Lobe Frontal Voluntary muscle movement, speech, reasoning, problem solving, emotions, personality Parietal Receive and process sensory information from the skin (pressure, temperature, pain) Process info responsible for spatial awareness Occipital Vision Temporal Auditory processing (hearing, speech) Verbal memories Phineas Gage

Cerebral Cortex The outermost layer of gray matter making up the superficial aspect of the cerebrum Cerebral Cortex

Name the Lobes Frontal lobe Parietal lobe Temporal lobe Cerebellum Occipital lobe Temporal lobe Cerebellum

Thalamus At base of the forebrain Relay station between spinal cord and cerebrum Receives sensory impulses from receptors Sorts and files information like a secretary

Hypothalamus Lies just below the thalamus Critical in homeostatic feedback loops Regulates BP, heart rate, body temperature Controls basic drives (hunger, thirst) and emotions (fear, rage, pleasure) Links nervous and endocrine systems

Midbrain Processes info from sensory neurons in the eyes, ears and nose Relays visual and auditory info between the forebrain and hindbrain Controls eye movement and skeletal muscle

Hindbrain Controls the autonomic system Regulates breathing, coughing, vomiting, etc. Activates the brain to maintain arousal or reduces arousal for sleep

Cerebellum 2nd largest region of the brain Coordinates muscle movement, balance, and posture

Brain Stem Connects the brain and spinal cord Control center for autonomic activity 2 main regions: Pons Medulla oblongata 1. 2.

Medulla oblongata & Pons Both structures found in the brain stem Controls autonomic homeostatic functions Heart rate Blood vessel activity Depth of breathing, swallowing, coughing Relays information to & from higher brain centers

Reticular Formation Part of the brain stem that regulates the sleep cycle, among other things Part of the pons, but not clearly defined as it also has projections into the thalamus and cerebrum Sleep & wakefulness produces patterns of electrical activity in the brain recorded as an EEG most dreaming occurs during REM (rapid eye movement) sleep EEG = ElectroEncephaloGram

Review of the Main Structures of the Brain 1. Cerebrum 2. Corpus callosum 3. Cerebellum 4. Medulla oblongata 5. Spinal cord 6. Pons 7. Hypothalamus 8. Thalamus

Limbic system: Your Lizard Brain Portion of the brain that deals with emotions, mood, memories and arousal Mediates basic emotions like fear, anger, sadness, etc. Composed of the: Hypothalamus  homeostatic control Hippocampus  involved in the formation of new memories Amygdala  raw emotions (aggression, fear, arousal, etc.), involved in recognizing facial expressions, possibly anxiety?, sexual orientation?? Cingulate gyrus  pathway to transmit messages

Let’s Have Some Fun with That Brain of Yours Optical Illusions

The Spinal Cord Composed of billions of neurons Acts as a pathway to and from the brain Located in the vertebral column Enables reflex actions

Cross-Section of the Spinal Cord Axons run to and from the brain and outward to the body Peripheral nerves enter and exit through openings in each vertebra Within each vertebra, each nerve separates into: dorsal roots  sensory nerves ventral roots  motor nerves

Quiz Time! 6 1 7 8 2 9 3 10 4 5 11

Quiz Time! Parietal Lobe Frontal Lobe Corpus Callosum Occipital Lobe Hypothalamus Thalamus Temporal Lobe Cerebellum Pons Medulla Oblongata Spinal Cord

Mammalian Brain Examine a mammal’s brain and locate as many brain structures as possible You will need: Gloves Dissecting tray Probe Goggles ½ sheep brain Gather your materials and have a look! Corpus callosum Cerebrum Cerebellum Pons Medulla

Locate the Following Structures The 3 regions of the brain Corpus callosum The 4 cerebral lobes Brain stem Cerebellum Thalamus Hypothalamus Pituitary gland Pons Medulla Spinal cord