Name: __KEY______Period: ______
Nervous packet continued…
CHAPTER 11: AUTONOMIC NERVOUS SYSTEM
I. COMPARISON OF SOMATIC AND AUTONOMIC NERVOUS SYSTEMS
OBJ: Compare the main structural and functional differences between the somatic and autonomic parts of the nervous system.
Somatic nervous system (SNS) includes both _sensory_ and _motor_ neurons.
Somatic sensory neurons convey input form receptors for the special senses:
· _vision______
· _hearing______
· _taste______
· _smell______
· _equilibrium______
Also receptors for somatic senses:
· _pain______
· _temperature______
· _touch______
· _proprioceptive sensations______
These are all consciously perceived…
Sensory motor neurons synapse with _skeletal muscle_ and produce _conscious, voluntary
movements_.
Skeletal muscles also generate _breathing_ movements.
Autonomic sensory neurons are associated with sensory receptors that monitor _internal
conditions_.
· _blood CO2 levels______
· _degree of stretching in walls of internal organs or blood vessels______
Autonomic motor neurons regulate _cardiac_ and _smooth_ muscles, and _glands_.
These cannot be consciously suppressed or altered.
Comparison of somatic and autonomic motor neurons
Somatic motor neurons extend from _CNS_ to _skeletal muscle fibers that it stimulates_.
Autonomic motor pathways consist of _two_ motor neurons.
_preganglionic neuron______Has cell body in CNS
_postganglioninc neuron______Lies entirely in PNS
Autonomic also has two main branches:
· _sympathetic division______
· _parasympathetic division______
Define dual innervation: _organs that receive impulses from both sympathetic and
parasympathetic neurons_ end of page 10
COMPARISON OF SOMATIC AND AUTONOMIC MOTOR NEURON PATHWAYS TO THEIR EFFECTOR TISSUES.
II. STRUCTURE OF THE AUTONOMIC NERVOUS SYSTEM
OBJ: Identify the structural features of the autonomic nervous system.
Preganglionic neurons, ganglia, and postganglionic neurons and how they relate to the activities
of the ANS.
READ THROUGH THIS SECTION, PAGES 278-283; EXAMINE THE DIAGRAMS. TAKE NOTES IN THE
SPACES PROVIDED, QUESTIONS ON THIS WILL BE MINIMAL ON THE TEST.
A. Organization of the Sympathetic Division
Also called thoracolumbar division because of outflow of sympathetic nerve impulses comes from thoracic and lumbar segments of spinal cord; cell bodies of preganglionic neurons in 12 thoracic and first two lumbar segments of spinal cord and extend to sympathetic ganglion where they synapse with postganglionic neurons. Most sympathetic preganglionic neurons are short but have many branches thus can synapse with many postganglionic neurons that in turn synapse with autonomic effectors. Most postganglionic from superior cervical ganglion associated with sweat glands, smooth muscles of the eye, blood vessels of the face, nasal mucosa, and salivary glands; few associated with others from middle and inferior cervical ganglion supply the heart. In thoracic region postganglionic axons from sympathetic trunk serve heart, lungs, and bronchi also some sweat glands, blood vessels, and smooth muscle of hair follicles in skin. Postganglionic neuron in abdomen follow arteries courses to abdominal and pelvic autonomic effectors. This division also includes adrenal glands, inner part adrenal medullae; these cells release hormones into the blood (epinephrine & norepinephrine); these hormones intensify responses elicited by sympathetic postganglionic neurons.
B. Organization of the Parasympathetic Division
Also called craniosacral division because of outflow of parasympathetic nerve impulses come from cranial nerve nuclei and sacral segments of spinal cord; cell bodies of parasympathetic preganglionic neurons located in nuclei of four cranial nerves (III, VII, IX, and X) in brain stem and in three sacral segments of spinal cord (S2, S3, and S4). Preganglionic neurons emerge from CNS as part of cranial nerve or anterior root of spinal nerve. Vagus nerve (cranial nerve X) carries 80% of parasympathetic outflow. Thorax axons of vagus nerve extend to ganglia in heart and airways of lungs; in abdomen they extend to ganglia in liver, gallbladder, bile ducts, stomach, pancreas, spleen, small intestine, transverse colon, and descending colon. Preganglionic axons from sacral segments extend to ganglia in walls of ascending colon, sigmoid colon, ureters, urinary bladder, and reproductive organs. Preganglionic and postganglionic synapse in terminal ganglia located close to or actually with wall of the innervated organ. These have short postganglionic neurons; parasympathetic responses are localized to a single effector.
III. FUNCTIONS OF THE AUTONOMIC NERVOUS SYSTEM; pages 283-285
OBJ: Describe the functions of the sympathetic and parasympathetic divisions of the autonomic
nervous system.
A. ANS Neurotransmitters
Check the appropriate neurotransmitters in the chart below:
Neurotransmitter / Acetylcholine / NorepinephrineSympathetic preganglionic neurons / all
Parasympathetic preganglionic neurons / all
Sympathetic postganglionic neurons / all
Parasympathetic postganglionic neurons / A few / Most
B. Activities of the ANS
1. Sympathetic Activities—“Fight or Flight”
List the “E” situations that could bring on stress:
_exercise______excitement______
_emergency______embarrassment______
List examples of “Fight or Flight” responses:
· _pupils of eyes dilate______
· _heart rate, force of heart contraction, and blood pressure increase______
· _airways dilate, allowing faster movement of air into and out of lungs______
· _blood vessels that supply nonessential organs (kidneys, GI tract constriction), which reduces blood flow through these tissues; result is slowing of urine formation and digestive activities, not essential during exercise______
· _blood vessels supply organs involved in exercise or fighting off danger (skeletal muscles, cardiac muscles, liver, and adipose tissue) dilate, allowing greater blood flow through these tissues______
· _liver cells break down glycogen to glucose, adipose cells break down triglycerides to fatty acids and glycerol, providing molecules that can be used by body cells for ATP production______
· _Release of glucose by liver increases blood glucose level______
· _processes not essential for meeting stressful situation are inhibited______
2. Parasympathetic Activities—“Rest and Digest”
What are the functions of the parasympathetic responses of the body? _supports body functions that conserve and restore body energy during times of rest and recovery______
What does SLUDD stand for? _salivation, lacrimation, urination, digestion, and defecation_
What type of responses are the five things listed above? _parasympathetic_
CHAPTER 12: SOMATIC SENSES AND SPECIAL SENSES
I. OVERVIEW OF SENSATIONS
OBJ: Define a sensation and describe the conditions needed for a sensation to occur.
A. Definition of a Sensation
What four conditions must be satisfied in order to be able to experience a sensation?
(1) _stimulus or change in environment, activate certain sensory neurons, i.e : form of light, heat, pressure, mechanical energy, or chemical energy______
(2) _sensory receptor must convert stimulus to electrical signal which produces one or more nerve impulses if it is large enough______
(3) _nerve impulses must be conducted along a neural pathway from sensory receptor to brain___
(4) _region of brain must receive and integrate nerve impulses into a sensation______
B. Characteristics of Sensations
Explain how we have perceptions. _conscious sensation –“eyes see” ;specialized sensory neurons integrated in cerebral cortex where they are interpreted ______
What is the relationship between perception and adaptation? _adaptation is a decrease in strength of a sensation due to prolonged stimulus which may lead to perceptions fading or disappearing even though stimulus persists______
C. Types of Sensory Receptors
Look over Table 12.1 on page 291, you will be using this information soon…
Label the following sensory receptors in the skin and subcutaneous layer pictured below:
a. Meissner corpuscles (Corpuscles of touch) e. Hair Root Plexuses
b. Pacinian corpuscles (Lamellated corpuscles) f. Nociceptors
c. Ruffini corpuscles (Type II cutaneous mechanoreceptors)
d. Merkel Disks (Type I cutaneous mechanoreceptors)
II. SOMATIC SENSES
OBJ: Describe the location and function of the receptors for tactile, thermal, and pain sensations.
Identify the receptors for proprioception and describe their functions.
A. Tactile Sensations (Mechanoreceptors)
Which sensations are tactile? _touch, pressure, vibration, itch, and tickle______
What are they detected by? _itch and tickle = free nerve endings; all others encapsulated nerve
endings_
1. Touch
Two types of rapidly adapting touch receptors:
· _Corpuscles of touch (Meissner corpulses)___
· _Hair root plexuses______
Two types of slowly adapting touch receptors:
· _Type I cutaneous mechanoreceptors (Merkel disks)______
· _ Type II cutaneous mechanoreceptors (Ruffini corpulses)__
2. Pressure and Vibration
How is pressure different from touch? _pressure is a sustained sensation felt over a larger area than touch______
Pressure receptors: _Type I mechanoreceptors and lamellated (pacinian) corpulses_
What types of receptors detect lower frequency vibrations? _corpulses of touch_
Higher frequency vibrations? _lamellated corpulses_
3. Itch and tickle
How are itch sensations stimulated? _stimulation of free nerve endings by certain chemicals like bradykinin, often a result of local inflammatory response______
What type of receptors sense itch and tickle? _free nerve endings______
Can you tickle yourself? _NO_ Why or why not? _impulses are conducted to and from cerebellum when you are moving your fingers and touching yourself does not occur when someone else tickles you______
B. Thermal Sensations (Thermoreceptors)
What type of receptors are thermoreceptors? _free nerve endings______
What are the two distinct types of thermal sensations? _coldness and warmth____
Temperatures between 10° and 40°C (50-105°F) activate _cold receptors_; located in the _epidermis_.
Temperatures between 32° and 48°C (90- 118°F) activate _warm receptors_; located in the _dermis_.
Below 10°C and above 48°C stimulate what type of receptors? _nociceptors_
These receptors produce what type of sensations? _painful sensations_
C. Painful Sensations (Nociceptors)
What type of receptors are nociceptors? _free nerve endings______
Where are nociceptors found? _almost every tissue of body except brain______
List five different stimuli that can cause pain
· _excessive stimulus of sensory receptors; ex: bright light in your eyes______
· _excessive stretching of structure______
· _prolonged muscle contractions; ex: hold weight for a long time______
· _inadequate blood flow to organ______
· _certain chemical substances______
Describe what is meant by referred pain. _pain felt in skin above or located near but not in organ_
Describe what is meant by fast pain. _within 0.1 seconds of stimulus; acute, sharp, or prickling pain; localized not in deep tissue_
Describe what is meant by slow pain. _begins a second or more after stimulus is applied; chronic burning, aching, throbbing; skin deep tissue and internal organs_
D. Proprioceptive Sensations (Proprioceptors)
Inform you consciously and unconsciously of _degree to which your muscles are contracted, the amount of tension present in your tendons, the positions of your joints, and the orientation of your head_
Receptors for these sensations are called: _proprioreceptors_ and they are located in _skeletal muscles, tendons, in and around synovial joints, and in inner ear_.
They adapt slowly and only slightly
What is kinesthesia? _perception of body movements, allows you to walk, type, or dress without using your eyes_
III. SPECIAL SENSES
Allow us to detect things in our environment…
IV. OLFACTION: SENSE OF SMELL (Chemoreceptors)
OBJ: Describe the receptors for olfaction.
CHARACTERISTICS OF RECEPTORS:
· _first-order neuron of olfactory pathway______
· _tips are protected by olfactory hairs______
· _stimulated by odorants; inhaled chemicals______
· _cells live about a month and then replaced______
V. GUSTATION: SENSE OF TASTE (Chemoreceptors)
OBJ: Describe the receptors for gustation.
CHARACTERISTICS OF RECEPTORS:
· _chemicals known as tastants stimulate them______
· _ electrical signal stimulate release of neurotransmitter molecules that bind to gustatory receptors on dendrites of taste buds’ first-order neurons_
· _respond to any one of five primary tastes: sweet, sour, bitter, salty, or umami (savory, glutamate detection)_
Let’s try something, everyone get a piece of gum. Unwrap the gum, hold your nostrils closed, place the piece of gum in your mouth and chew, and then let go of your nostrils).
VI. VISION (Photoreceptors)
OBJ: Describe the receptors for vision.
Identify the structures of photoreception and how they work. _retina is the beginning of visual pathway; three layers: photoreceptor layer, bipolar cell layer, and ganglion cell layer. Two types of cells in photoreceptor layer: rods (allow us to see shades of gray in dim light,like moonlight) and cones (stimulated by brighter light- highly acute, color vision). Stimulation of photoreceptors have photopigment which absorbs light and then undergo change in structure to adjust to amount of light available; in rods photopigment is rhodopsin)___
VII. HEARING AND EQUILIBRIUM (Mechanoreceptors)
OBJ: Describe the receptors for hearing and equilibrium.
The ear has three principle regions: the outer ear, the middle ear, and the inner ear.
Physiology of Hearing
Describe events 1-8 pictured below involved in simulations of hair cells by sound waves.
(1) _auricle directs sound waves into external auditory canal______
(2) _sound waves strike eardrum; produce vibrations, eardrum vibrates in response______
(3) _central area of eardrum connects to malleus that also starts to vibrate, vibration moves from malleus to incus to stapes______
(4) _stapes moves back and forth, pushes the oval window in and out______
(5) _movement of oval window sets up fluid pressure waves in perilymph of cochlea. Inward movement of oval window pushes perilymph of scala vestibuli______
(6) _pressure waves move from scala vestibuli to scala tympani and eventually membrane covering the round window causing it to bulge into the middle ear______
(7) _pressure waves deform walls of scala vestbuli and tympani pushing vestibular membrane back and forth, creating pressure waves in endolymph inside cochlear duct____
(8) _pressure in endolymph cause basilar membrane to vibrate, which moves hair cells of the spiral organ against tectorial membrane. Bending of hairs stimulates hair cells to release neurotransmitter molecules at synapses with sensory neurons that are part of vestibulocochlear nerve, sensory neurons generate nerve impulses along nerve and sound is received and interpreted_
Physiology of Equilibrium
Describe static equilibrium and its function. _maintenance of the position of the body relative to the force of gravity; maintains posture and balance by providing sensory information on the position of the head______
Describe dynamic equilibrium and its function. _maintenance of body position in response to sudden movements such as rotation, acceleration, and decleration; reestablish balance to disturbed equilibrium by regulating sensitivity of hair cells in the ear______
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