EXSC 224 Lab Exam 2

Brainstems role in ANS

-Midbrain, pons, medulla oblongata -Part of myelencephalon -Controls involuntary functions of the respiratory, digestive and circulatory systems and contributes to hearing, balance, and taste -Autonomic reflex center for heart contraction, vasomotor control, respiratory rate and depth as well as other critical reflexes such as swallowing, coughing, vomiting, and sneezing

Hypothalamus role in ANS

-One of three regions of diencephalon -Contributes to homeostasis and is the main visceral control center of the brain -Consists of nuclei such as mammillary, tuberal, preoptic, and supraoptic -Endocrine control via the pituitary gland, regulation of autonomic nervous system and part of limbic system with participates in the emotions of pleasure, fear, and rage

pre/post ganglionic nerve fibers in parasympathetic division

-Preganglionic fibers are lightly myelinated group B fibers of moderate diameter. -Postganglionic fibers are unmyelinated group C fibers.

eye structure

3 tunics fibrous vascular retina

retina parts

A) Pigmented layer B) Neural layer -photoreceptors -bipolar cells -ganglion cells

posterior pituitary hormones

ADH and oxytocin

brain regions used for vision

CN 2 optic nerve occipital lobe, thalamus, midbrain, hypothalamus

· Which cranial nerves transmit information for taste?

CN VII, CNX, CNIX

Olfactory brain regions

CN: 1 Olfactory forebrain segment limbic system amygdala mammillary bodies

pinna and external auditory canal function

Captures sound waves and concentrate them into canal

What is a hormone? What are the two major chemical categories of hormones?

Chemical messengers released by glands that effect a separate part or the body than they were released Amino acid and steroid

· What cranial nerves are associated with the parasympathetic division? What is their role? What about sacral nerves?

Cranial: CN: III (oculomotor), VII (facial nerves), IX (glossopharyngeal), X (vagus) S2-S4

How do we taste?

Food enters mouth and we chew it the chewed food spreads over the various PAPILLAE tastants bind to the TASTE BUD receptors on the papillae The receptors create a signal that travels through one of the 3 cranial nerves, depending on location Signals go to the MEDULLA and then the THALAUS

What are the associated structures for the olfactory pathway?

Forebrain segment (sensory perception both smell and taste), limbic system (olfactory processing), amygdala (smell and memory of smell), mammillary bodies (olfaction information relays through here)

anterior pituitary hormones

Growth hormone (GH) Thyroid-stimulating hormone (TSH) Adrenocorticotropic hormone (ACTH) Follicle-stimulating hormone (FSH) Luteinizing hormone (LH) Prolactin (PRL)

what are the main control systems for the ANS

Hypothalamus and brain stem

· What structures in the brain are responsible for assisting in governing the autonomic nervous system functions?

Hypothalamus and brainstem

· Describe the structure of the autonomic nervous system.

Hypothalamus and brainstem parasympathetic and sympathetic systems

· Describe the general process of olfaction including the pathway of gustation.

Molecules enter through from air to nasal pathways and reaches olfactory bulb -> stimulate the cilia of olfactory neuron found in bulbs --> neural impulse to the brain --> reaches olfactory impulse that interprets the signal

process of vision

Photoreceptors in Retina →Optic Nerve → Crosses Optic Chiasma →Optic Tracts → Lateral geniculate bodies in Thalamus → Visual Cortex of Occipital Lobe

Describe the pathway of light from source to optic nerve to optic chiasm to occipital lobe

Retina optic nerves optic chiasm optic tracts lateral geniculate bodies optic radiations visual cortex

Rods

Retinal receptors that detect black, white, and gray

Are there more rods or cones? Which has higher acuity?

Rods Cones

tympanic membrane function

Separates inner and outer ears, transfers sound to vibrations

What is the optic chiasm?

Site in the forebrain where the right and left optic nerves intersect

What structures house the sensory receptors for this pathway?

Some taste receptors on soft palate and in throat, but most on tongue

What is the pathway of sound from the external environment to the brain? Describe the mechanisms involved in this special sense.

Sound, outer ear canal eardrum vibrations malleus, incus, stapes cochlea, vibrates tiny hair cells on corti, then to pons

hearing pathway

Sound, outer ear --> canal -->eardrum vibrations --> malleus, incus, stapes -->cochlea, and then to pons

cochlea function

Spiral shaped, fluid filled, vibrations push against membrane filled with thousands of tiny hair cells

pre/post ganglionic nerve fibers in sympathetic division

Sympathetic preganglionic (group B) fibers secrete ach at synapse. Postganglionic fibers are unmyelinated (group C) and secrete NE. (Adrenal medulla response is also important and hormonal effects are a large reason why sympathetic stimulation is more chronic than parasympathetic.)

Thyroid hormones

T3, T4, calcitonin

parasympathetic division

The branch of the autonomic nervous system that generally conserves bodily resources.

What is the hypophyseal portal system? Describe the relationship between the hypothalamus and pituitary.

The system of vasculature that connects the hypothalamus and the anterior pituitary is called the hypophyseal portal system. The hypothalamus is the master endocrine gland. It secretes hormones that regulate the pituitary. Hormones from the hypothalamus and pituitary regulate all major body functions.

· What other special sense is closely associated with taste?

Touch

Describe the stress response from an endocrinological perspective.

adrenal glands stimulated

adrenal cortex hormones

aldosterone, cortisol, androgens

Mechanism of smell

chemoreceptors

mechanism of taste

chemoreceptors

vascular tunic

choroid, -ciliary body, iris, pupil, lens

inner ear

cochlea, vestibule, semicircular canals

Cones

color

· Where are the nerves for this pathway found? Based off this, what is another name for the para/sympathetic division?

craniosacral for parasympathetic thoracolumbar

optic chiasm function

enables vision from one side of both the eyes to be appreciated by the occipital cortex of the opposite side

adrenal medulla horomones

epinephrine and norepinephrine

Kidney hormones

erythropoietin and renin

ovaries

estrogen and progesterone

What are the important external structures for olfaction's? Internal structures?

external: nose Internal: olfactory bulb

Accesory Eye Structures

eyelids, eyelashes, tarsal/ciliary glands, lacrimal apparatus

How is blood glucose regulated by the pancreas?

glucagon and insulin

How do hormones affect a target tissue? What is responsible for mediating this process?

hormones effect target tissue by binding to there receptors and forming proteins receptors mediate responses

parasympathetic nerves arise from...

in the brain stem and sacral spinal cord

What are the major structures of the inner ear?

inner -cochlea -vestibule -semicircle canals

Pancreas

insulin and glucagon

Raynaud's disease

intermittent and painful cyanotic attacks in the extremities due to an exaggerated sympathetic response to cold or stress. Severity can vary

Hypertension

may be due to overactive sympathetic stimulation from chronic stress. This increases load on heart as well as artery walls and can lead to any number of CVD. Commonly treated, at least in part, with beta blockers (adrenergic receptor blockers)

mechanism of equilibrium

mechanoreceptors

mechanism of hearing

mechanoreceptors

What are the major structures of the middle ear?

middle -tympanic membrane -auditory tube -mallus, incus, stapes

ear areas

outer, middle, inner

What are the major structures of the outer ear?

outer/external -pinna/auricle -external auditory canal

parathyroid hormones

parathyroid hormone (PTH)

mechanism of sight

photoreceptors

external ear

pinna and external auditory canal

Where are olfactory receptors located?

roof of nasal cavity

fiberous tunic

sclera and cornea

What structures are associated with our sense of equilibrium? Compare and contrast the two major structures involved in this process.

semicircle canals and cilia involves the cerebellum and ends in the pons

Senses

sight, taste, touch, smell, and hearing

· Describe the roles of the sympathetic and parasympathetic divisions of the ANS.

sympathetic •The sympathetic division ramps up body functions during periods of increased activity parasympathetic •Activates resting processes like digestion and waste elimination to maintain bodily function and conserve energy

Senses of touch

temperature, pressure, pain

Testes

testosterone

sympathetic nervous system

the division of the autonomic nervous system that arouses the body, mobilizing its energy in stressful situations

the sympathetic nervous system produces...

the fight or flight response stressful situations

autonomic nervous system (ANS)

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. involuntary

sympathetic nerves arise from...

thoracic and lumbar spinal cord

middle ear

tympanic membrane auditory tube ossicles (malleus, incus, stapes)

Autonomic dysreflexia

uncontrolled activation of autonomic neurons. Common in quadriplegia or those with spinal cord transection above T6.

Special senses

vision, hearing, taste, smell, equilibrium

· Are there functions unique to the parasympathetic division?

•Activates resting processes like digestion and waste elimination to maintain bodily function and conserve energy

Gustation (taste)

•CN: VII Facial (anterior taste), X Vagus (posterior taste, throat), IX Glossopharyngeal (back of the tongue) •Brain regions: -Insula (taste) -Medulla oblongata (taste) -Forebrain segment (sensory perception, taste/smell)

Balancing (ear)

•CN: VII Vestibulocochlear •Brain regions: -Temporal Lobe (auditory cortex) -Pons (process acoustic and vestibular info) -Medulla (hearing taste, balance)

· What is the role of the autonomic nervous system? What functions does it command? Is this located in the PNS or CNS?

•Continually alters in-order to maintain homeostasis or to support functions •The autonomic nervous system controls involuntary visceral activities like heart rate, respiration, digestion, glandular secretions, and reproduction PNS

parasympathetic division function

•Digestive activity •Urinary activity •Heart rate decreases •Airway diameter decreases

what are secondary endocrine glands?

•Gonads •Kidneys •Heart •Thymus

· Are there any pathologies associated with the ANS?

•Hypertension •Raynaud's disease •Autonomic dysreflexia

What are the primary endocrine glands?

•Hypothalamus •Pituitary gland •Pineal gland •Thyroid gland •Parathyroid glands •Adrenal glands •Pancreas

Describe the pathway an impulse would follow through the PARASYMPATHETIC system. What structures would it pass through? What neurotransmitters are involved? Is their more than one potential pathway?

•Preganglionic nerve fibers (group B fibers) synapse with postganglionic fibers (group C fibers) which pass the signals on to their target organs. Craniosacral Pre: ACh Post: ACh

· Describe the pathway an impulse would follow through the SYMPATHETIC system. What structures would it pass through? What neurotransmitters are involved? Is their more than one potential pathway?

•Preganglionic nerve fibers pass signals from the spinal cord to the sympathetic trunk (paravertebral) ganglia. After synapsing they become postganglionic fibers (or adrenal medulla) and pass the signals on to their target organs. Thoracolumbar pre: ACh, Post: NE

· Describe the functions of the autonomic nervous systems.

•The autonomic nervous system controls involuntary visceral activities like hear rate, respiration, digestion, glandular secretions, and reproduction •Continually alters in-order to maintain homeostasis or to support functions

· Are there functions unique to the sympathetic division?

•The sympathetic division produces the fight-or-flight response during stressful situations •Pupils dilate •Airways dilate •Skeletal muscles receive more blood •Heart rate increases •Increased sweat gland activity