Teas 7 Nervous System (7)

Process of hearing

1. Sound waves are funneled by auricle into external acoustic meatus (eardrum) 2. Tympanic membrane vibrated which causes movement of ossicles (bones) 3. Stapes moves oval window, transmitting sound to inner ear 4. Pressure waves in perilymph of scala vestibuli deform cochlear duct 5. Region of basilar membrane that matches sound frequency is displaced 6. Stereocilia of hair cells are bent leading to impulses in cochlear branch of vestibulocochlear nerve

brain stem function

1. control heartbeat/circulatory functions 2.breathing 3. Digestion

Glutamate

A major excitatory neurotransmitter; involved in memory

Dopamine

A neurotransmitter associated with movement, attention and learning and the brain's pleasure and reward system.

Acetylcholine

A neurotransmitter that triggers muscle contraction

afferent vs efferent neurons

Afferent neurons are sensory neurons that carry nerve impulses from sensory stimuli towards the central nervous system and brain, while efferent neurons are motor neurons that carry neural impulses away from the central nervous system and towards muscles to cause movement. PNS

Axon structure and function (axon hillock, axon terminals)

An axon is a smooth, cable-like nerve fiber that is specialized to conduct electrical impulses away from the soma. Most neurons have one long axon, but the axon's length can vary, and some neurons have no axon at all. The axon emerges from a slightly elevated structure called the axon hillock that connects the soma to the axon. The cytoplasm of the axon is called axoplasm, and it lacks the Golgi bodies, Nissl bodies, and ribosomes found in dendritic cytoplasm. Since there is little to no translation, proteins must be imported from the soma. The axon often splits into collaterals that allow one neuron to interact with more than one cell. At the end of each axon are highly branched structures called axon terminals. These club-shaped endings contain synaptic vesicles filled with neurotransmitters. When an action potential is generated at the axon hillock, it propagates along the axon. When it reaches the axon terminals, the neurotransmitters are released to a target cell.

sacral plexus

Arises from L4-S4 - Serves the buttock, lower limb, pelvic structures, and perineum

Norepinephrine (NE)

Brain arousal and other functions like mood, hunger, and sleep Influences mood and sleep patterns

brachial plexus

C5-C8, T1

Efferent neuron's ganglia/relfex arc

Comes from anterior horn no ganglion

Meninges of the brain

Dura mater - adheres to skull and to arachnoid. Your dura mater contains a drainage system, called the dural venous sinuses, which allows blood to leave your brain and allows cerebrospinal fluid to re-enter the circulation. Innervated, and vascularized. Contains two layers the Endosteal layer which lines the cranium bones and the meningeal layer which lines the vertebral cavity Arachnoid - contains connective tissue but not nerves or blood vessels Pia mater - adheres to brain following sulci/gyri; blood enters brain through it. It acts as a barrier and aids in the production of cerebrospinal fluid. Vascular CSF is in the subarachnoid space

how crista ampullaris works

During rotation, endolymph moves inside the semicircular canals in the direction opposite of the rotation. Endolymph flow bends the cupola and excited the hair cells As rotational movement slows, endolymph keeps moving in the direction of the rotation, bending the cupola in the opposite direction from acceleration and inhibiting the hair cells This will tell us the direction we are turning. Bending of the hair cells one way will hyperpolarize and the other way will depolarize.

Once sensory information has been processed,

Effector neurons (motor neurons) transmit the impulse away from the CNS to activate muscles and glands All motor neurons of the somatic division run directly from the CNS to the effect with out synapsing with another neuron. The autonomic division uses 2 neuron pathway

positive feedback

Feedback that tends to magnify a process or increase its output. Less common, and sometimes harmful because they enhance the stimuli rather than inhibit. A beneficial form of positive feedback occurs during childbirth. When the cervix is stretched by the descending fetus, impulses are sent to the pituitary which sends a command to increase the contractions. Also when there's an infection—> more immune cells r sent

Oligodendrocytes

Form myelin sheath in CNS Unlike Schwann cells, a single Oligodendrocyte Can myelin dozens of axons by extending its membrane in multiple directions and wrapping around the axons.

What lobes are the brain divided into and what is their function

Frontal, parietal, occipital, temporal The frontal lobe is responsible for short term in working memory and information processing as well as decision-making, planning, and judgment Parietal: sensory input as well as spatial positioning of the body

3 main parts of the brain and what they each contain

Hindbrain: includes the medulla oblongata, cerebellum, and pons Midbrain: integrate sensory signals in orchestrates responses to these signals Forebrain: includes the cerebrum, thalamus, and hypothalamus

cranial nerves

I. Olfactory II. Optic III. Oculomotor IV. Trochlear V. Trigeminal VI. Abducens VII. Facial VIII. Vestibulocochlear IX. Glossopharyngeal X. Vagus XI. Accessory XII. Hypoglossal Oh oh oh, to touch and feel very good vagina ah heaven

ganglion cells

In the retina, the specialized neurons that connect to the bipolar cells; the bundled axons of the ganglion cells form the optic nerve. anglion cells collect information about the visual world from bipolar cells and amacrine cells (retinal interneurons

What structure vibrates when sound waves strike it

It collects sound waves and channels them into the ear canal (external auditory meatus), where the sound is amplified. The sound waves then travel toward a flexible, oval membrane at the end of the ear canal called the eardrum, or tympanic membrane. Sound waves cause the eardrum to vibrate. tympanic membrane vibrates

lumbar plexus

L1-L4

Excitation of rods: dark to light

Light absorbed by rhodopsin will trigger a series of reactions in which retinal will change its shape from cis (bent) to trans (straight) and will release opsin.

Schwann cell structure

Neurons of the peripheral nervous system are myelinated by Schwann cells. They wrap around the axon The nucleus and cytoplasm remain outside of the myelin sheath but are incased in the outer neurilemmal. Axons a very small diameter may be supported by Schwann cells but are not myelinated by them. These are called non-mylenated Schwann cells.

Signal transmission in the retina (whole process in the light)

PHOTORECEPTOR CELLS (rod): 1. Retinal will go into trans (straight) form in the presence of light. 2. The trans form of the pigment will activate a G protein (called transducin). A cause a series of reactions (phototransduction) through G protein system. 3. Which at the end, closed a cation channel and hyperpolarizes the cell BIPOLAR CELLS: 1. ^^ since photoreceptor channels are closed —> neurotransmitters ARENT released. This actually causes bipolar cells to be excited. 2. Results in depolarization of bipolar cells 3. Opens channels and releases neurotransmitter to ganglion cells GANGLION CELLS: 1. EPSP occurs and ganglion cells sends action potential to the brain

negative feedback

Process in which the response to an in balance act servers or reduce the change. The maintenance of body temperature is one of the many examples. As body temperature changes, Thermoreceptors send information to the hypothalamus. If body temperature is too high, a command is sent to dilate blood vessels and release sweat. A type of regulation that responds to a change in conditions by initiating responses that will counteract the change. Maintains a steady state. A primary mechanism of homeostasis, whereby a change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation.

PNS glial cells

Schwann cells and satellite cells

What hormones does the anterior pituitary produce

TSH, FSH, GH, LH, Prolactin, adrenocorticotropic hormone (Thyroid stimulating hormones, follicle stimulating hormone)

reflex arc/In the spinal cord, the cell bodies of afferent neurons reside in

The dorsal root ganglia just outside of the spinal cord. Afferent fibers enter into the posterior/dorsal aspect of the spinal cord, a region called the posterior gray horn through the anterior route

Structure of spinal cord (grey vs white matter)

The gray matter of the spinal cord contains neuron cell bodies; the white matter consists of myelinated axons that occur in bundles called tracts. Because these tracts cross over, the left side of the brain controls the right side of the body and vice versa. The spinal cord is a major reflex center that connects the afferent and efferent pathways. It is made of an exterior layer of white matter that surrounds an interior core of gray matter. White matter: consists of glial cells and myelinated bundles of axons that form tracts to and from the brain. There are no cell bodies or dendrites in white matter Grey matter: consists of interneurons and contains motor neurons and glial cells. The oxons are mostly unmilitated giving the tissue its gray appearance.

The nervous and endocrine are linked via

The hypothalamus

Divisions of the nervous system

The nervous system is divided into two main parts: 1. Central Nervous System (CNS) 2. Peripheral Nervous System (PNS) -ANS (autonomic) -sympathetic and parasympathetic -SNS (somatic)

parasympathetic nervous system

The parasympathetic nervous division is responsible for the "rest and digest" response. Both pre- and postganglionic neurons of the parasympathetic nervous system release acetylcholine. The parasympathetic nervous system stimulates events that are slower-paced, and less essential for immediate survival. Heart rate and respiration rate decrease, blood flow is directed to digestive organs, peristalsis is promoted, pupils constrict, and glycogen is synthesized.

sympathetic nervous system

The sympathetic nervous division is responsible for triggering the "fight or flight" response. Preganglionic neurons of the sympathetic nervous system release acetylcholine (ACh), which is the stimulus for the release of norepinephrine from postganglionic neurons. Norepinephrine acts on target tissues, prompting a rapid and unified response. The heart rate increases, respiration rate increases, blood flow to the heart and skeletal muscle increases, pupils dilate, and glycogen is broken down.

Basic of auditory transduction

The vibration that is in the air is going to come to your tympanic membrane. Then it's going to come to the auditory ossicles (bones). Then to the oval window. Then to the perilymph. Then to the endolymph then to hair cells. These hair cells are Mechanoreceptors. Tympanic membrane——> auditory ossicles —-> oval window—-> perilymph—-> endolymph ——> hair cells (These hair cells are Mechanoreceptors & bending of them open or closed ion channels which will hyperpolarize or depolarize the hair cells which will then be converted to the brain).

What are the gaps between the myelin sheath called what is the point

They are called the nodes of Ravenier this allows the impulse to quickly jump from one node to the next It increases the rate of conduction

Where are visceral sensory receptors found and what do they detect

They are found in the walls of internal organs and blood vessels Detect stretch, changes and chemical concentrations, temperature, and pain

How are neurons of the peripheral nervous system myelinated

They are myelinated by Schwann cells. These Giulio cells curve around the axon, wrapping their plasma membranes around like a bandage to form multiple lipid Rich layers.

To see far away, the ciliary muscle _______ and the suspensory ligament's are ______

To see far away, ciliary muscles are relaxed in the suspensory ligament's are stretched

sympathetic nervous system and parasym thicc nerve system

Uses a two neuron pathway, consisting of a preganglionic neuron which runs from the CNS to a ganglion and a postganglionic neuron which innervates the effector

Synaptic Process

When an action potential reaches the axon terminal, voltage gated calcium channels open in response to the depolarization of the membrane. Calcium ions enter, triggering the release of neurotransmitters by exocytosis. The neurotransmitters diffuse across the synaptic cleft, binding to receptors in the target sell in eliciting either an excitatory or inhibitory response. The Neuro transmitters are than recycled back to the presynaptic cell energy created by enzymes were diffuse away from the synaptic cleft to prevent overstimulation

GABA

a major inhibitory neurotransmitter

The hypothalamus

a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion Controls the ANS and the pituitary "Produces" oxytocin and antidiuretic hormone (ADH) (tell the pituitary to secrete it and store it)

Histamine

a neurotransmitter that plays an important role in stimulating wakefulness, and works at the hypothalamus. Allergy symptoms

amacrine cells and horizontal cells

amacrine-Specialized retinal cells that contact both the bipolar cells and the ganglion cells, and are especially significant in inhibitory interactions within the retina. Amacrine cells receive inputs from bipolar cells while horizontal cells receive inputs from photoreceptors.

CNS glial cells and function

astrocytes, microglia, ependymal cells, oligodendrocytes

types of synapses

axodendritic, axosomatic, axoaxonic Axoaxonic are rare terminating on a postsynaptic axon

Central nervous system

brain and spinal cord Integrate sensory information

gilial cells

cells in the nervous system that support, nourish, and protect neurons

What covers the cerebrum?

cerebral cortex

regions of the spinal cord

cervical, thoracic, lumbar, sacral

types of sensory receptors

chemoreceptors, mechanoreceptors, photoreceptors, thermoreceptors, nociceptors, exteroceptors, proprioceptors, interoceptors Sensory neurons are the afferent neurons that deliver impulses to the CNS Mechanoreceptors respond to pressure or tension. Cutaneous touch receptors such as Meissner's corpuscles, Meritel's disks, Pacinian corpuscles, and Ruffin endings are all mechanoreceptors, as are the muscle spindles that detect the stretching of skeletal muscle and the receptors of the inner ear that detect vibration Chemoreceptors such as olfactory and taste receptors detect the presence of chemicals Photoreceptors such as the rod and cone cells of the eye respond to light. Thermoreceptors sense both absolute temperature and changes in temperature. Nociceptors detect pain Sensory neurons can also be categorized by location. Exteroceptors near the body surface information about the external environment. Proprioceptors within the inner ear, Skeletal muscles, and joints provide information about movement, position, and equilibrium. Interoceptors of visceral organs and blood vessels provide information about internal stimuli

What is the structure of the inner ear

cochlea

cranial cavity contains

contains the brain, cranial nerves, and the pituitary gland

cercumen

ear wax

bipolar cells

eye neurons that receive information from the retinal cells and distribute information to the ganglion cells. Bipolar cells are one of the main retinal interneurons and provide the main pathways from photoreceptors to ganglion cells,

phasic receptors

fast adapting Quickly adopt to a constant simulist, meaning that action potential's decreased overtime and eventually stop. This explains the loss of sensation of clothes against the skin or how an odor seems to disappear when the source is still present

Which part of the brain regulates heart rate, respiratory rate, and blood pressure

medulla oblongata

Brainstem consists of and function

midbrain, pons, medulla oblongata Midbrain: functions in motor movement, particularly movements of the eye, and in auditory and visual processing Pons: Sends sensory info to cerebellum, breathing Medulla: can access spinal cord to the brain. Plays an important role in the autonomic nervous system in the circulatory and respiratory system

What hormones do the posterior pituitary secrete

oxytocin and ADH

2 types of sensory receptors

phasic and tonic

What is the correct order of the meningeal layers of the brain from inside to outside

pia mater, arachnoid, dura mater

Visual pathway

retina -> optic nerve -> optic chiasm -> optic tracts -> lateral geniculate nucleus (LGN) of thalamus (and synapse there) -> visual radiations -> visual cortex

reflex arc

sensory receptor, sensory neuron, motor neuron, and effector that are involved in a quick response to a stimulus Describes a neural pathway that triggers a reflex action. begins with the 1. receptor (site or organ that recieves stimukus) 2. sensory neuron that will carry the impulse along the afferent pathway to the 3. integration center within the CNS 4. interneurons will process info and pass the impulse down to the 5. motor neurons and travels along the efferent pathway to the 6. effector or the responding muscle or gland

tonic receptors

slowly adapting receptors that respond for the duration of a stimulus Ex: Proprioceptors, photoreceptors, nociceptors

Cerebellum

the "little brain" at the rear of the brainstem; functions include processing sensory input and coordinating movement output and balance Also plays a role in the processing and storing of implicit memories. Specifically for those memories developed during classical conditioning learning techniques

Somatic nervous system

the division of the peripheral nervous system that controls the body's skeletal muscles

Synapse

the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron

corpus callosum

the large band of neural fibers connecting the two brain hemispheres and carrying messages between them

Saltatory propagation

the movement of an action potential along a myelinated axon, "jumping" from node to node Faster and more efficient than the continuous conduction scene among unsheathes axons

Autonomic nervous system

the part of the peripheral nervous system that controls the glands and the muscles of the internal organs (such as the heart). Its sympathetic division arouses; its parasympathetic division calms. Controls involuntary movements and glandular secretions. The autonomic nervous system has to subdivisions the sympathetic and the parasympathetic Sympathetic division activates flight or fight that increases heart rate, dilate pupils, the bronchial tubes, and suppresses functions that are not required for survival The parasympathetic division activates the rest and digest functions by decreasing heart rate, constricting pupils in bronchial tubes, and promoting digestion

Peripheral nervous system

the sensory and motor neurons that connect the central nervous system to the rest of the body Consists of nervous tissues, nerves and ganglia that are outside of the central nervous system. It sends information to and from the central nervous system allowing it to communicate to the rest of the body. Further divided into the autonomic nervous system and the somatic nervous system Contains afferent and efferent neurons

Dura mater

thick, outermost layer of the meninges surrounding and protecting the brain and spinal cord Interovated, vast realize, outer layer that lies next to the bones and folds in words to separate the brains into different compartments. Contains two layers Endosteal/periosteum : which lines the cranial bones. The spinal cord dura mater has no periosteal layer. Meningeal layer: Lines the vertebral cavity in lies beneath the Endosteal layer

Structures of the middle ear

tympanic membrane, ossicles, eustachian tube