Central Nervous System CNS Brain and spinal cord

• Central Nervous System (CNS) – – Brain and spinal cord • Peripheral Nervous System (PNS) – – Made up of nerves that attach to CNS

Peripheral Nervous System P e rip h e ra l N e rvo u s S yste m S ke le ta l (S o m a tic) A u to n o m ic S ym p a th e tic P a ra sym p a th e tic

Functional Subdivisions of the PNS • PNS contains 2 functional subdivisions – Sensory (afferent) nerves conduct sensory impulses to CNS from receptors in organs and tissues – Motor (efferent) nerves conduct impulses away from CNS to muscle effectors and glands

• Somatic Nervous System (SNS) – – Controls voluntary and involuntary skeletal muscle contractions – Involuntary skeletal contraction – reflex – Single neuron system • Autonomic Nervous System (ANS) – – Controls activity of smooth and cardiac muscles – 2 neuron system • 1 st: from CNS to ganglion • 2 nd: from ganglion to effector Subdivisions of Motor Division (PNS)

Subdivisions of ANS • Sympathetic division – – Fight or flight • Parasympathetic division – – Regulates resting functions • Ex. , digesting food

• “ Fight or flight” response • Release adrenaline and noradrenaline • Increases heart rate and blood pressure • Increases blood flow to skeletal muscles • Inhibits digestive functions Sympathetic CENTRAL NERVOUS SYSTEM Brain Dilates pupil Stimulates Inhibits salivation Relaxes bronchi Spinal cord Salivary glands Lungs Accelerates heartbeat Inhibits activity Heart Stomach Pancreas Stimulates glucose Secretion of adrenaline, nonadrenaline Relaxes bladder Sympathetic ganglia Stimulates ejaculation in male Liver Adrenal gland Kidney

Parasympathetic • “ Rest and CENTRAL NERVOUS SYSTEM digest ” system • Calms body to conserve and maintain energy • Lowers heartbeat, breathing rate, blood pressure Brain Contracts pupil Stimulates salivation Spinal cord Constricts bronchi Slows heartbeat Stimulates activity Stimulates gallbladder Contracts bladder Stimulates erection of sex organs Gallbladder

Summary of ANS differences Autonomic nervous system controls physiological arousal Sympathetic division (arousing) Pupils dilate Decreases Parasympathetic division (calming) EYES Pupils contract SALIVATION Increases Perspires SKIN Dries Increases RESPIRATION Decreases Accelerates HEART Slows Inhibits DIGESTION Activates Secrete stress hormones ADRENAL GLANDS Decrease secretion of stress hormones

• Made up primarily of 2 types of cells: – Neurons – Supporting cells • CNS - neuroglia (glial cells) – Astrocytes, microglia, ependymal cells, oligodendrocytes • PNS – satellite cells, Schwann cells

• Made up of a cell bodies, dendrites, and axons • Cell body (or soma) – Contains large nucleus and Nissl bodies (Rough E. R. ), primary site of protein synthesis – Most located within CNS where they are protected by hard bones of skull and vertebral column – Collection in CNS is called “nuclei” whereas in PNS they are called “ganglia” Neurons

More on Neuron Structure • Dendrites – Short, highly branched signal receptive regions of nerve cell – Convey incoming message toward the cell bodies • Each nerve cell (neuron) has only one axon – Impulse generating and conducting region of neuron

Myelin Sheath of the Axon • Whitish, fatty protein layer • Serves to protect and electrically insulate axon • Increases the speed of transmission of nerve impulses (up to 150 times faster) • Only associated with axons, not dendrites

REVIEW: Functional Classification • Neurons are grouped according to the direction in which the nerve impulse travels relative to the CNS • Based on this there are sensory, motor, and association neurons – Sensory – transmit impulses from skin or other organs toward CNS – Motor – carry impulses away from CNS to effector organs – Association (interneurons) – lie between motor and sensory neurons

Neuron Video neurilemma

Neuroglia (CNS) • CNS has 4 different types of supporting cells (neuroglia) – Abundant and diverse – Limited knowledge of each function due to difficulty in isolating individual cells • Ependymal cells – Line central cavities of brain and spinal cord – Beating of cilia help to circulate the cerebrospinal fluid (CSF) – CSF: protection of brain and transport of vital nutrients and waste • Astrocytes – Attach neurons to capillaries, linking them to nutrient supply

Neuroglia CONT…. • Oligodendrocytes – Branches wrap around neuron fibers, forming an insulating covering called a myelin sheath • Microglia – Monitor health of nerve cells – If foreign invader detected or cell damaged, many microglia head to the area, transform into macrophages, and protect the CNS by phagocytizing the microorganisms or neuronal debris

Neuroglia (CNS)

Label your Synapses Diagram Use pages 392 and 406 in the AP book • HINTS FOR YOU: = Sodium ions = Potassium ions = Calcium ions = synaptic vesicles w/ neurotransmitters = chemical gated channels

Action potential • http: //highered. mcgrawhill. com/sites/0072495855/stude nt_view 0/chapter 14/animation__t he_nerve_impulse. html

ANIMATION OF CHEMICAL SYNAPSES • http: //highered. mcgrawhill. com/sites/0072495855/stude nt_view 0/chapter 14/animation__ chemical_synapse__quiz_1_. html Animation of ENTIRE SYNAPTIC PROCESS with ACTION POTENTIAL

Sodium/Potassium Pump • http: //highered. mcgrawhill. com/sites/0072495855/stude nt_view 0/chapter 2/animation__h ow_the_sodium_potassium_pump _works. html

Action Potential Graph • Know what happens at each part of the graph with relationship to the pre-synaptic and postsynaptic activities. • Look at the HANDOUT with the graph!!

• Also known as “Nerve Impulses” • Self-regenerating wave of electrochemical activity that allows neurons to carry a signal over a distance (“game of telephone”) • Pulse-like waves of voltage that travel along several types of cell membranes • http: //outreach. mcb. harvard. edu/animations/ actionpotential. swf

• Initiation/Resting Stage: – Some K+ channels are open: K+ diffusion occurring – Initiated by stimulus above a certain intensity or threshold (~-70 m. V – resting potential) – Could be a pin prick, light, heat, sound or an electrical disturbance in another part of the neuron (“telephone call”) – Electrical signal rises from changes in permeability of the neuron’s axon membranes to specific ions (Na+ & K+)

Depolarization (Rising Phase) • • • K+ Channel gates are closed Stimulus causes gate in the Na+ Channel to open High concentration of Na+ outside, Na+ diffuses into neuron • Electrical potential changes to ~ +40 m. V. Repolarization (Falling Phase) • Depolarization causes K+ Channel gate to immediately open & Na+ Channel close • K+ diffuses out of neuron • Reestablishment of initial electrical potential of ~-60 m. V.

Refractory Period (Recovery Phase) • Na+ & K+ Channels cannot be opened by a stimulus • Na+/K+ Pump actively (ATP) pumps Na+ out of & K+ into neuron • Reestablishment of ion distribution of resting neuron • This AP acts as stimulus to neighboring proteins & initiates AP in another part of neuron • Wave of APs travel from dendrites to axon terminals • At axon terminal, electrical impulse is converted to a chemical signal (neurotransmitter)

Per. 2 start, Fri Per. 4, WU go over handout http: //bcs. whfreeman. com/thelifewire/content/chp 44/4402002. html

• Getting the message across (the synapse)? – http: //www. mind. ilstu. edu/curriculum/neurons_intro. php – At axon terminal, chemical signal (NT) crosses synapse between adjacent neurons • Starts AP on this neuron – This activates Ca 2+ channel to open • Ca 2+ diffuses into neuron • Causes NT vesicles to move to end & fuse with cell membrane • Through exocytosis, NTs are released into synapse – NTs diffuse across synapse & bind to NT receptors on another neuron • Causes Na+ channels to open & AP is initiated in next neuron

• Information from one neuron flows to another neuron across a synapse… – a small gap separating neurons that consists of: – a presynaptic ending that contains neurotransmitters, mitochondria & other organelles, – a postsynaptic ending that contains receptor sites for neurotransmitters & – a synaptic cleft or space between the presynaptic & postsynaptic endings.

Let’s Review… How do neurons communicate? • What is another name for the nerve impulse that travels from the axon hillock through the axon to the axon terminal? • What are the 4 main phases of an Action Potential? • What happens in the Rising Phase? • Falling Phase? • Recovery Phase? • Resting Potential? • What ion entering the neuron instigates the movement of synaptic vesicles to the cell membrane? • What do the vesicles release into the synapse? • What happens after the NTs are released into the synapse?

Central Nervous System Brain Spinal Cord • Brain and Spinal Cord

• Average adult male’s brain weighs approximately 1. 6 kg (~3. 5 lbs) • Average female’s: 1. 42 kg • According to body weight, though…they are relatively equal in size

Brain has 2 Hemispheres • Left & Right sides are separate • Corpus Callosum : major pathway between hemispheres • Some functions are ‘lateralized’ – Language, numbers on left – Color and music on right • Lateralization is never 100% Corpus Callosum Right Hemisphere Left Hemisphere

Corpus Callosum • Major ( but not only) pathway between sides • Connects comparable Medial surface of right hemisphere structures on each side • Permits data received on one side to be processed in both hemispheres • Aids motor coordination of left and right side Corpus Callosum

Contralateral Motor Control • Movements controlled by motor area • Right hemisphere controls left side of body • Left hemisphere controls right side • Motor nerves cross sides in spinal cord Motor Cortex Somatosensory Cortex

Each hemisphere is divided into 4 lobes Frontal Parietal Occipital Temporal Cerebellum

• Cover and protect CNS • Protect blood vessels and enclose venous sinuses • Contain cerebrospinal fluid • Form divisions within the skull

Matter • Deep to the gray matter of cortex • Aids communication between cerebral areas and between cerebral cortex and lower CNS • Spinal cord has just the opposite type of matter http: //www. brainexplorer. org/brain-images/white_matter. jpg

Frontal Lobe • Contains primary motor cortex • No direct sensory input • Important planning and sequencing areas Broca’s area for speech • Prefrontal area for working memory Frontal Lobe Working Broca’s Memory Area Motor Cortex

Occipital Lobe • Input from Optic nerve • Contains primary visual cortex Occipital Lobe – most is on surface inside central fissure • Outputs to parietal and temporal lobes Visual Lobe

Temporal Lobe • Inputs are auditory, Contains primary auditory cortex visual patterns – speech Auditory recognition Cortex – face recognition – word recognition – memory Temporal formation Lobe • Outputs to limbic System, basal Ganglia, and brainstem

Parietal Lobe • Inputs from multiple senses borders visual & auditory cortex Outputs to Frontal lobe hand-eye coordination eye movements attention Somatosensory Parietal Cortex Lobe

• Cerebral Hemispheres – – Has outer cortex of gray matter (neural bodies) • Diencephalon – – Thalamus, hypothalamus, and epithalamus • Brain Stem – – Midbrain, pons, medulla • Cerebellum – – Has outer cortex of gray matter Regions & Organization

Label the worksheet on the brain!! • I will place the worksheet under the document camera for you to view!!

Cerebral Hemispheres • Approx. 83% of total brain mass • Covered with elevations called gyri and shallow grooves called sulci • Deeper grooves, called fissures, separate major regions of the brain

Cerebral Cortex • It is the gray matter of the cerebrum • Enables us to perceive, communicate, remember, understand, appreciate, and initiate voluntary movement – It enables conscious behavior • Contains 3 functional areas: – Motor – control voluntary motor functions – Sensory – provide conscious awareness of sensation – Association – integrate diverse information for purposeful action

The Brain Stem • Includes: – Midbrain – Pons – Medulla oblongata • Structurally different from brain because it has deep gray matter surrounded by white matter (similar to spinal cord) • Coordinates head and eye movement when we visually follow a moving object or see something out of corner of eye • Coordinates head reflex movement to unexpected auditory stimulus

The Diencephalon • Surrounded by the cerebral hemispheres • Consists of 3 bilaterally symmetric structures: http: //www. web-books. com/e. Library/Medicine/ Physiology/Nervous/diencephalon. jpg – – – Thalamus Hypothalamus Epithalamus

The Thalamus • Egg-shaped • Makes up 80% of diencephalon • Within the thalamus a sorting-out and information “editing” process occurs

The Hypothalamus • • Caps the top of the brain stem Main visceral control center of the body Vitally important to the homeostasis of the body A few of its functions: – Regulates involuntary nervous system activities (blood pressure, motility of digestive tract) – Perceives pleasure, fear, rage and sex drive (emotions) – Regulates body temp. by initiating – Regulates feelings of hunger and fullness – Regulates water balance and thirst – Regulates sleep cycle in response to daylight-darkness cues received by our eyes – Controls endocrine system functioning – hormonal balance

Epithalamus • Most dorsal portion of the diencephalon • Forms roof of 3 rd ventricle • Aids with sleep-wake cycle regulation (pineal gland) • Helps with CSF production

Pons • Helps to maintain normal rhythm of breathing Medulla Oblongata • “medulla” • Most inferior part of the brain stem • Adjusts the force and rate of heart beat and depth of breathing • Regulates vomiting, hiccupping, swallowing, coughing and sneezing

The Cerebellum • Coordinate skeletal muscle contractions needed for the smooth, coordinated movements of our daily lives – Ex. , driving, typing, walking • Cerebellar activity occurs subconsciously

Cerebrospinal Fluid • Functions: – Forms cushion for brain and other CNS organs – Gives buoyancy to brain (which reduces weight by 97%) to prevent brain from crushing under own weight – Also helps blood in providing brain with nourishment • Fun Fact: – Average adult brain contains 150 ml and is replaced every 3 -4 hours • Application: – If CSF becomes obstructed, can cause condition called hydrocephalus • Enlargement of the head in babies and brain damage in adults

Looks Can Be Deceiving v. What are these kinds of pictures called? v. What do these do to neuron communication within our Nervous System?

The Dancing Girl • Look at the Dancer… – Which way is she turning? • Clockwise? • Counter-clockwise? – Now stare at her bottom foot & squint your eyes… • Does she start turning the other direction?

Get lost in the circles • What happens when you focus on the center of a circle?

Anatomy WARM-UP • Read the article about Phineas Gage then answer the following questions: • • What was Phineas’ occupation? Why is the Phineas Gage story so popular among medical science? • Was there a change in Gage after the accident? • Where can you go and view Gage’s skull? 3 rd qtr; week 5; day 2

• On a separate paper, write your thoughts about this picture… • Your reactions • What do you think caused this situation? – Based on what you know, • what kind of repercussions would this accident have on the nervous system? – Now read the following story of Phineas Gages’ tragic accident… – Write about your reactions to the accident • What surprised you about any info learned? • What kinds of things does the prefrontal cortex (lobe) regulate?

Vision • Photoreceptors are the visual receptor cells • Adult eye averages 1 inch in diameter • Accessory structures of the eye protect the eye or aid in its functioning

Accessory Structures • • Eyebrows Eyelids Conjunctiva Lacrimal apparatus • Extrinsic Eye muscles

Lacrimal Apparatus PAGE 555 in AP book • Consists of the lacrimal gland lacrimal ducts • Lacrimal gland releases fluid that contains mucus, antibodies, and lysozyme (a bacteriadestroying enzyme) • Lacrimal gland is located superior and lateral to the eye – It releases fluid, which is spread over eye by blinking, and drains via the medial lacrimal canals

Eyebrows and Eyelids • Eyebrows overlie the supraorbial margins of the skull • They shade the eyes from sunlight and prevent perspiration from entering the eyes • Eyelids cover the eye when the orbicularis oculi contract –Eyelashes (palpabrae) are richly innervated, • This occurs (blinking) every three to seven so anything that seconds to prevent touches them, including a puff of air, desiccation of the eyes triggers reflex blinking

Structure of the Eyeball • Made up of three layers called tunics: fibrous (1), vascular (2) and sensory (3) • Fibrous tunic is the outermost coat of the eye • It is divided into two major regions: the cornea and the sclera • The sclera (tough connective tissue) is the “white of the eye” and functions to protect and shape the eyeball • Also serves as sturdy anchoring point for extrinsic eye musculature • PLEASE LABEL your wksht with color coding of your 3 tunics 3

• Though it seems to appear in many colors (Iris means rainbow), it actually only contains brown pigment • When an iris contains a lot of pigment, the eyes appear brown or black • If the amount of pigment is small, the short wavelengths of light are scattered from the unpigmented parts of the iris, and eyes appear blue, green, or gray • Why, then, do newborn babies often appear to have gray or blue eyes? ris (Vascular Tunic)

The Sensory Tunic Lens • Contains the lens (hard disc) which allows an image that is upside down and backwards. • This is the deepest layer and also has pigmented cells that absorb light • Also stores Vitamin A, which is needed by the Photoreceptor cells • The retina contains millions of photoreceptors known as cones and rods

CHECK YOUR LABELS!!!

Conjunctiva • A transparent mucous membrane that lines the eyelids and reflects over the surface of the eyeball • It functions to lubricate the eye and to prevent invasion to the posterior portion of the eye • Conjunctivitis is an inflammation of the conjunctiva; Pinkeye is a type of conjunctivitis caused by bacteria or virus

More on the Eye • Cornea is lined with pain fibers (which is why contacts can be so tough to adjust to) • When cornea is touched, reflex blinking and increased lacrimal fluid secretion occur • Since cornea has no blood supply it is the only tissue that can be transplanted with very little fear of rejection (does not have contact with immune system)

Internal Chambers • Filled with aqueous humor which is produced in the posterior chamber and drains from the anterior chamber • If this drainage is blocked, pressure within the eye may increase and cause compression of the retina and optic nerve-a condition called glaucoma • Exam to diagnose is simple…a puff of air at the sclera will produce a measurable amount of deformation

Colorblind Tests • http: //www. toledobend. com/colorblind/Ishihar a. html • http: //colorvisiontesting. com /online%20 test. htm#demons tration%20 card

ENDOCRINE SYSTEM • Responsible for sending messages to target organs by secreting hormones • Moves slower than the Nervous system

ENDOCRINE SYSTEM • Please label all of the glands on your wksht and explain what hormone is secreted from each of them. • Use pages 591 -692 in the Anatomy book! Yes, you will need to identify what the hormone does for the body…MAKE IT BRIEF!!

THE END

The Ear • Divided into three major regions: • Inner ear • Middle ear • Outer ear

LABEL YOUR WORKSHEET Page 573 in AP book •

• Auricle = the ear • made up of the helix (rigid portion) and lobule (no cartilage) • directs sound waves into auditory canal • canal is short (2. 5 cm) and curved and extends to the tympanic membrane • Canal is lined with hairs, sebaceous glands, and aprocrine sweat glands called ceruminous glands Outer Ear

Middle Ear • Small, air-filled cavity within the petrous portion of temporal bone • Eustachian tube links middle ear to superiormost part of the throat – Normally this is closed, but yawning and swallowing opens this tube briefly to equalize pressure

• Contains the three smallest bones in the body: the ossicles • Malleus (hammer) – secured to the tympanic membrane • Incus (anvil)- connects other bones • Stapes (stirrup) – connects to the inner ear (via the oval window) • Tensor tympani muscle attaches the auditory tube. The stapedius muscle runs from the wall of the middle ear cavity and

Inner Ear • Located deep within the temporal bone and posterior to the eye socket • Made up of the vestibule, cochlea, and semicircular canals

Vestibule • Central egg-shaped cavity that medially borders the middle ear • Has oval window in its lateral wall • Contains perilymph (similar to CSF) • Houses equilibrium Sensors called maculae that respond to the pull of gravity and report changes of head position

Semicircular Canals • Made up of an anterior, posterior, and lateral canal • Also have receptors to help with equilibrium

Cochlea • About half the size of a pea • Contains three hollow cavities: Scala vestibuli(terminates at oval window), cochlear duct, scala tympani (terminates at round window) • Cochlear duct contains spiral organ of Corti, which is the receptor organ for hearing

Hearing • Sounds set up vibrations in air that beat against the ear drum • This pushes the ossicles that press fluid in the inner ear against membranes • This pressure on the membranes pulls on tiny hair cells that stimulate nearby neurons that give rise to impulses that travels to the brain, where they are interpreted

Hair Cells in the Spiral Organ of Corti • Lining the organ of Corti you find roughly 16, 000 hearing receptor cells called cochlear hair cells sandwiched between basilar membrane and tectorial membrane

Deafness • Two types: conduction or sensorineural • Conduction deafness – occurs when something interferes with conduction of sound vibrations to the fluids of the innner ear • Sensorineural deafness – results from damage to neural structures at any point in the hearing pathway – This typically result from the gradual loss of the hearing receptor cells: • Throughout life • Single explosively loud noise • Prolonged exposure to high-intensity sounds, which cause these cells to stiffen (IPODs)