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
