A&P II Exam 1 Study Guide
Exam 1 Lecture Objectives:
Nervous System Review Information
Regulation and Integration of the Body, The Central Nervous System, Peripheral Nervous and Reflexes
Review over nervous system and describe the structure and function of the parts of the brain and spinal cord.
Understand the pathways of ascending and descending spinal cord tracts.
Understand the process of reflexes
The Autonomic Nervous System
Understand the anatomy and physiology behind the autonomic nervous system
The Special Senses
Describe the structure and function of the special senses which include the eye, the ear, the nose, the tongue.
Know the principles of hormones and mechanisms by which they work
The Endocrine System
Know the structure and function of the endocrine organs.
Know the purpose of the endocrine hormones and the disorders which can result from a loss in homeostasis of these hormones
Review over chapters 11-13
Sensory input (Afferent) - information about the internal and external environment
Integration (Brain and Spinal Cord) - The processing and interpretation of sensory input
Motor Output (Efferent) - The resulting activation of effector organs
The Nervous System can be divided into two principle parts the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). The CNS is comprised of the Brain and the Spinal Cord which occupy the Dorsal Cavity. It functions as the integration center and dictates all motor and glandular responses
The PNS is the component of the Nervous System that resides outside of the CNS and carries sensory input to and motor input away from the CNS.
The nerves that carry sensory information are called afferent nerves (“carrying towards”)
Somatic (body) - impulses from the skin, skeletal muscles, and joints
Visceral - impulses from the organs within the ventral body cavity
The nerves that carry motor information are called efferent nerves (“carrying away”)
Somatic - also known as the voluntary nervous system, sends impulses to the skeletal muscles
Visceral /Autonomic (ANS) - also know as the involuntary nervous system it sends impulses to smooth muscle, cardiac muscle, and glands.
Sympathetic - Regulate the body functions that prepare the body for the fight or flight response
Parasympathetic - Does the opposite of the Sympathetic usually leading to a conservation of energy
• Know some of the things regulated by the sympathetic and parasympathetic pathway….for instance in the Iris in the eye.
• Be able to tell me what pathway is involved in examples given to you and be able to name the full name….for instance Efferent Visceral Sympathetic would be one name
Ohms Law : Current (I) = Voltage (V) / Resistance (R)
Current is the flow of electrical charge from one point to another
Voltage is the measure of potential energy (mV)
Resistance is the hinderance to the flow of the energy through an object.
Insulators have high resistance while conductors have low resistance.
Neuronal Signaling
The axon begins with a Resting Membrane Potential (-70 V) where the inside of the cell is more negatively charged that the outside of the cell due to a higher concentration K+ and Anion proteins that have a negative charge. When a signal is being sent, the ion channels on the surface of the axons cause a shift in the amount of K+ and Na+ . The change in concentration can cause the cell to be depolarized (less negatively charged), repolarized, and hyperpolarized (more negatively charged).
*Know which ions are moving in or out depending on the phase of neuronal signaling and difference between depolarization, repolarization, and hyperpolarization
Conduction of the Neuronal Signal
The neuron conducting the impulse is the presynaptic neuron while the neuron receiving the impulse is the postsynaptic neuron
There are two varieties of synapes electrical and chemical
Electrical synapses are less common but are much faster than chemical synapses
Chemical Synapses are more common and use special neurotransmitters to signal responses
Neurotransmitters
Acetylcholine (ACH) - It is a neurotransmitter often used at neuromuscular junctions and in some autonomic neurons
Biogenic Amines - include Catecholamines (Dopamine, epinephrine, and norepinephrine) and the indolamines (serotonin and histamine)
Adenosine triphosphate - ATP
Amino Acids - include gamma aminobutyric acid (GABA), glutamate, and glycine
Peptides - include endorphines and Tachykinins
Be ready for any examples that were given in class to be asked
CNS
CNS- Central Nervous System - comprised of the brain and the spinal cord.
The average male human brain weighs about 1600g (3.5 lbs).
During development the ectoderm along the dorsal surface forms a structure called a neural plate. The neural plate invaginates forming a neural groove flanked by neural folds. Eventually the neural folds become neural crests and the groove seals to form a neural tube.
* Know the above paragraph completely
Brain Development
Telencephalon “end brain” - Cerebrum
Diencephalon “interbrain” - thalamus, hypothalamus (hypophysis and infundibulum), and epithalamus (pineal)
Mesencephalon “midbrain” - Brainstem: midbrain
Metencephalon “afterbrain” - Brainstem: Pons and cerebellum
Myelencephalon “spinal brain” - Brainstem: Medulla oblongata
CSF and Ventricles
Cerebrospinal fluid (CSF) is stored in the neural tube which develops into 4 main regions in the brain (Lateral ventricles, third ventricle, and fourth ventricle) and the central canal in the spinal cord. The two lateral ventricles are separated by a thin wall called the septum pellucidum, The third ventricle and fourth ventricle are connected together by a canal called the cerebral aqueduct
Know the pathway of CSF
Cerebral Cortex
Gyrus “Twisters” - Elevated ridges or folds
Precentral Gyrus - is primarily associated with motor movement.
Postcentral Gyrus - is primarily associated with sensory
Sulcus “furrows” - Shallow grooves
Central sulcus
Lateral sulcus/Lateral cerebral fissure
Fissures are deeper grooves
Longitudinal fissure
Transverse cerebral fissure
Cerebral Lobes
Frontal Lobe - Spatial tasks, object recall, multi-task problems, and learned motor movements
Parietal Lobe - Somatosensory area
Temporal Lobe - Hearing
Occipital Lobe – Vision
Insula -
Thalamus- “Inner Room”
Interthalamic adhesion
Corpus Callosum
Lateral Ventricle
Basal Nuclei
Caudate Nucleus
Lentiform Nucleus
Putamen
Globus Pallidus
Other Brain Structures
Mammillary Bodies – Relay Center for Olfactory Pathways
Infundibulum – Tissue that connects the Hypothalamus to the Pituitary
Pituitary – Major endocrine gland
Hypothalamus – Below the thalamus
Functions of the Hypothalamus:
Autonomic Control Center, Center for emotional response, Body temperature regulation, Regulation of food intake, Regulation of water balance and thirst, Regulation of Sleep-wake cycles, and Control of endocrine system functioning.
Brainstem
Midbrain
Cerebral Peduncles – Corticospinal tracts
Corpora quadrigemina
Superior Colliculi – Visual reflex centers
Inferior Colliculi – Auditory relay centers
Substantia Nigra – This is a relay region for the basal nuclei and degeneration to this region leads to Parkison
Pons – Acts as the bridge between the projections of brain and the Spinal Cord
Medulla Oblongata – Continuation of the brainstem that leads seamlessly into the spinal cord
Cerebellum
Accounts for 11% of the total brain Mass
Provides precise timing, coordinated movement and agility
Emotions
Limbic System (Limbus –ring)- is the structure responsible for emotions and emotional responses. Made up of the septal nuclei, cingulate gyrus, parahipocampal gyrus, dentate gyrus, hippocampus, amygdala, hypothalamus, and thalamus
Memory
Hippocampus is the major brain region important for converting short term memory over to long term memory
The Cerebral cortex is where our conscious mind is found. It is the outer layer of the brain, the gyri, which is composed of gray matter. It makes up 40% of the brain’s weight.
K. Broadman mapped out the brain into 52 mosaic areas now known as Broadman’s area. These areas were later used by scientists to associate functionality with the cortex.
Homunculus means “little man”
Neuronal Disorders
Multiple Sclerosis is an autoimmune disease which attacks the myelin of nerve cells.
Symptoms include visual disturbance (including blindness), problems controlling muscles (weakness, clumsiness, and ultimately paralysis), speech disturbances, and urinary incontinence.
Alzheimer’s - A disease that primarily strikes people over 65. Causes a degeneration of neurons that lead to dementia and a loss of memory
Parkinson’s - A disease that typically strikes people in their 50s and 60s. Causes persistent tremor movement of the body even at rest and are slow to initiate and execute movement
Huntington’s - A disease that primarily strikes people in their 40s. A fatal hereditary disorder, kills within 15 years of symptom onset, chorea (“dance”).
Cyclopia - A disease caused by trisomy at chromosome 13 (having three instead of two).
During development and prior to birth, the brain develops more rapidly than it should causing the shape of the skull to change. This forces the nose upward to form a proboscis (tube shaped nose) and the eyes to merge into one spot.
Spina Bifida – Neural tube defects are one of the more common congenital anomalies. There are three types of spina bifida.
Occulta - mildest form and only affects the vertebra causing it to be malformed
Meningocele occurs when the open neural tube defect forms with a lack of a skin covering allowing the meninges to protrude through the defect.
Meningomyelocele also known as Spina Bifida Cystica - the most serious form of spina bifida, the meningeal membranes that cover the spinal cord and part of the spinal cord protrude through a cleft, forming a sac or cyst. There is usually some degree of paralysis and loss of sensation below the damaged vertebrae. Many children and adults with this condition experience problems with bowel and bladder control. In 90% they also have hydrocephalus, extra fluid in the ventricles of the brain.
Rachischisis - An Extreme form of Spina Bifida where by the brain and spinal cord are exposed to the environment. Often times the development of those structures is halted due to exposure to amniotic fluids.
Anencephaly - Anencephaly occurs when there is failure in the formation of the fetal cranial vault.
Iniencephaly with Rachischisis - when there is a lack in the proper formation of the occipital bone and upper cervical vertebrae causing a shortened neck and defect in the upper cord. Individuals are born with their head in a tilted back position.
Exencephaly - When the cranial vault of a developing fetus is not completely present. However since the brain was not exposed to amniotic fluid, the brain still develops. Such an event is very rare and may be resultant from craniofacial clefts associated with the limb-body wall complex and early amnion disruption.
Encephalocele - a neural tube defect cased by the failure of thhe neural tube to close completely during fetal development
Hydranencephaly - a rare cephalic disorder caused by an abnormal development of the fetal tube where the cerebral hemispheres are absent and replaced by saces filled with cerebrospinal fluid
Nasopharyngeal Teratoma - Congenital and pediatric neoplasms are uncommon. One type that can occur is a teratoma. Shown here is a large nasopharyngeal teratoma that is protruding from the oral cavity.
* Know examples of people who have the disorders and/or know what it looks like
Spinal Cord
Central Canal
ANterior Median fisure
Posterior Median Septum
Spinal Ganglion
Grey Commissure - connects left and right side of spinal cord so it allows for sensory information to come in, cross over, and go to the brain.
Pia mater
Dura mater - touches skull and vertebrae
Arachnoid - connective tissue connecting the pia mater and dura mater
Espstein Bar Virus - causes mono
Ascending Spinal Tracts
Fasciculus Gracilis and Fasciculus Cuneatus – System which conveys information for discriminative touch, conscious proprioception, and vibration sense to the cerebral cortex
Spinocerebellar – System which conveys information to the cerebellum for movement coordination
Spinothalamic - transmits pain, temperature, itch and crude touch.
Descending Spinal Tracts
Reticulospinal – Conveys impulses regulating cardiovascular and respiratory functions and affects muscle tonus and somatic movement
Rubrospinal - responsible for large muscle movement such as the arms and the legs
Corticospinal - involved in manipulation and fine movements of the distal parts of the limbs
Vestibulospinal – Conveys postural control, especially related to movements of the head, and in the coordination of head and eye movements.
Tectospinal - Mediates contralateral movements of the head in response to auditory, visual and somatic stimuli
Characteristics of the Cranial Nerves
Olfactory - Smell
Optic - Vision
Oculomotor - Movement of the eye
Trochlear - Movement of the eye
Trigeminal - Made up of the ophthalamic, Maxillary, and Mandibular Nerves
Abducens - Movement of the eye
Facial - controls muscles of the face and taste
Auditory (Vestibulocochlear) - Hearing
Glossopharyngeal - reflexes of the heart, taste, and swallowing
Vagus - Helps to regulate the heart, lungs, and digestive organs
Accessory - Sternocleidomastoid and trapezius muscle
Hypoglossal - Muscles of the tongue
Know the names of the different spinal regions, plexi, and the number of nerves in each region
Know what Cauda equina is and what it means
Chapter 15 Special Senses
Taste and Taste Buds
Taste – “to touch, estimate, or judge”
Soft palate, inner cheeks, pharynx, epiglottis and tongue are all able to taste
Papillae – Small projections that contain the taste buds
Filiform – Do not contain taste buds
Fungiform – More numerous mushroom shaped
Circumvallate – (7-12) in back of tongue Circular in shape
Sweet, Salty, Sour, Bitter, and Umami
Sweet – Responds to sugars, saccharin, alcohols, amino acids, and some lead salts.
Sour – Responds to Hydrogen Ions (H+)
Salty – Responds to Metal Ions (inorganic salts) and Table salt (NaCl)
Bitter – Responds to alkaloids (quinine, nicotine, caffeine, morphine, and strychnine) and some non-alkaloids such as aspirin
Umami – Responds to Glutamate and is associated with the beef taste of steak, zest of ripe tomatoes, and the tang of aging cheese
What is the G-protein associated with bitter and sweet tastes?
Taste
Supporting cells – insulate and protect gustatory cells
Gustatory cells – are actual chemoreceptor cells for taste
Gustatory hairs – are long microvilli that extend from gustatory and supporting cells
Basal cells – are stem cells which divide and form new support cells which later form Gustatory cells (taste cells are replaced every ?? - ?? days)
Three nerves responsible for Taste are
Facial Nerve (Cranial Nerve VII) - anterior two thirds of tongue
Glossopharyngeal Nerve (Cranial Nerve IX) – posterior third of tongue
Vagus Nerve (Cranial Nerve X) – pharyngeal region
Gustatory Pathway
Nerves for taste run from the mouth to the Solitary Nucleus in the medulla oblongata. The nerves synapse and cross over to the contralateral side and head towards the thalamus where they synapse again and head towards the Gustatory Cortex in the Parietal lobe.
Taste is 80% Smell
The mouth contains receptors for temperature (Thermoreceptors), pain (Nociceptors) and pressure (Mechanoreceptors)
Temperature and texture can influence how one tastes
Spicy foods work by stimulating pain receptors
Olfaction – means to smell derived from latin meaning to sniff or to smell and to do
Do smells have weight?
Humans can distinguish 10,000 or so different smells
There are 1,000 known smell genes which encode for odorant binding proteins
Smells which have pungent or sharp smells such as ammonia and hotness found in chili peppers stimulate pain receptors
Similar to taste buds the olfactory receptor cells are surrounded by supporting cells and Lipofuscin gives the olfactory epithelium the yellowish hue
Basal cells function by replacing olfactory neurons every 60 days
Mechanism of smell
Odorant binds to receptors attached to G-proteins. Upon binding the G-protein changes configuration and activates adenylate cyclase. Adenylate cyclase converts ATP into cAMP cAMP then activates a Na+ channel which creates an action potential in the neuron that starts the pathway.
Pathway of Smell
Olfactory receptors nerves synapse at the glomeruli to mitral cells in the olfactory bulb. Axons from mitral cells form the olfactory tracts which can then head either to either the Thalamus and then to the frontal cortex and olfactory cortex (smells are interpreted and identified) or to the Hypothalamus, amygdala, and limbic system (associate memory and emotions to smells). Glomeruli only bind one type of odorant
What does Glomeruli mean?
What is the protein secreted by olfactory glands to produce mucus?
Granule cells in the olfactory bulb release GABA in order to inhibit mitral cells
Smells associated with danger activate the flight or fight response
Smells associated with foods can stimulate the body to prepare for digestion
Smells that are associated with unpleasant odors can cause a protective reflex (sneezing or choking)
Disorders of Smell
Anosmia’s – “without smells” – results from injuries that tear the olfactory nerves in the nasal cavity
Uncinate fits – are olfactory hallucinations that can be psychological or caused by irritation of the olfactory pathway or by epileptic seizures
Exterior of the Eye
70% of all the sensory receptors in the body are in the eye
Obicularis Oculi – closes the eyelids
Lateral and Medial Canthus –the junction where the upper and lower orbicularis oculi muscle meets
Epicanthic folds – tissue that covers the canthus and gives an Asian appearance to the eyes
Caruncle – fleshy elevation at the medial canthus that produces an oily secretion
What is the average diameter of the human eye?
Palpebrae (eyelid)
Levator Palpebrae – elevates the eyelids
Conjunctiva – a continuous clear mucous membrane that line internal surface of the eyelid (Palpebral) and the anterior surface of the eyeball (Bulbar (ocular conjunctiva))
Lacrimal system (apparatus)
Lacrimal Gland – Gland that secretes tears
Lacrimal Duct – Empties tears from gland onto the conjunctiva of the eye
Lacrimal canals – carry tears to the lacrimal sacs
Lacrimal Sacs – empties tears into nasolacrimal duct
Nasolacrimal duct – empties tears into inferior meatus of nasal cavity
Lysozyme – Lytic enzyme in tears
Ciliary gland – sweat gland between eyelash hair follicles
Internal Anatomy of the Eye - Tunics – internal layers of the eye
Fibrous (outtermost) – dense avascular connective tissue
Sclera – opaque white “white’s of the eye”
Cornea – transparent portio
Uvea (middle)– Vascular connective tissue
Choroid – blood rich nutritive layer containing a dark pigment
Ciliary body – Contains muscles which change the shape of the lens
Ciliary process – Secretes the aqueous solution which empties into the anterior segment of the eye providing pressure and nutrients on the lens
Scleral venous sinus – drains the aqueous solution in the anterior chamber into lacrimal punctum
Iris – most anterior part of the uvea which separates the eye into anterior and posterior segments
Pupil – Rounded opening which light passes through
Sensory (innermost)
Retina
Pigmented epithelial layer
Neural layer – contains the photoreceptors (Rods and Cones) which detect light
Optic Disc – the area of the eye where the optic nerve leaves eyeball (blind spot)
Macula lutea – area of high cone density (yellow spot)
Fovea Centralis – a pit in the macula lutea about 0.4mm in diameter where greatest visual acuity occurs
Vitreous body or humor – is a gel-like substance that fills the poster segement of the eye
Lens – focuses light toward the retina
Ciliary zonule (suspensory ligament) – holds the lens in place
Know the wave lengths of different lights
420nm – blue, 530nm – green, and 560nm – red
Pathway of vision
Nerves from the eye (optic nerve) travel to the optic chiasm where they split into ipsilateral and contralateral optic tracts. The tracts will travel to pretectal nucleus, superior colliculi, and thalamus.
From the thalamus the tract will continue to the occipital lobe
From the Pretectal nucleus the tract travels to the spinal cord while the tract
From the superior colliculi are relayed to other parts of the brain including the hypothalamus and limbic system
Disorders of the Eye
Tarsal gland –Large sebaceous gland found posterior to the hair follicles
Sty – Inflammation of the ciliary or small sebaceous gland
Conjuctivitis – Inflammation of the conjunctiva
Giant Papillary Conjunctivitis
Conjunctivial Papiloma with foreign body
Fungal Corneal Ulcer
Cataracts – when the lens becomes increasingly hard and opaque
Glaucoma – pain and possible blindness caused when intraocular pressure reaches dangerously high levels
Color Blindness – Inability to see a frequency of light
Myopia – Nearsightedness – corrected with a concave lens
Hyperopia – Farsightedness – corrected with a convex lens
Diplopia – Double Vision
Strabismus – Cross-eyed
Astigmatism – Unequal curvatures on the lens
Nyctalopia – Night Blidness
Traumatic Enucleation – traumatic injury forces the eye out of socket
Retinal Detachment – Retina becomes detached from the pigmented retina
Vitreous Hemorrhage – Blood vessels in the choroid burst filling the posterior cavity
Identifying structures of the Ear
External Ear
Auricle (Pinna) – skin covered cartilage that is suppose to funnel sound
Lobule – most inferior portion of the pinna
External acoustic meatus – opening leading into the skull
Ceruminous glands –secretes a waxy material
Tympanic membrane (eardrum) – Vibrates in response to sound waves hitting it
Middle Ear
Tympanic cavity – the cavity which contains the osicles
Osicles – Malleus (hammer), Incus (anvil), Stapes (stirrup) – amplifies and transmits the sound waves coming from the eardrum into the oval window
Pharyngotympanic or auditory tube – connects the nasopharynx to the middle ear in order to equalize pressure on the middle ear with respect to external pressure
Why is this important?
Inner Ear
Labyrinth – bones which contour to form the inner ear
Perilymph – an aqueous fluid found in the labyrinth which contains the membranous labyrinth
Endolymph – viscous fluid found in the membranous labyrinth
Vestibule and Semicircular canals - important for maintaining balance and equilibrium
Cochlea – responsible for hearing
Frequency Vs Amplitude
Frequency – The number of waves that pass over a given period of time
Low pitch has less frequency
High pitch has more frequency
Amplitude – The height of the wave indicates the strength of wave.
Loud sounds will have more amplitude
Soft sounds will have less amplitude
Sounds 20,000Hz (High notes) at the Base of cochlear – 20Hz (Low notes) at the
Apex of the cochlear
Pathway of Hearing
Signals from the cochlear are sent from the Spiral organ of Corti in the cochlear to the Spiral ganglion where they join nerves from the vestibule to form the vestibulocochlear nerve (auditory) where they travel to the cochlear nuclei. From the cochlear nuclei the nerves cross over to synapse at the Superior Olivary Nucleus. The nerves travel towards the brain where it synapses at the inferior colliculi. From the inferior colliculi to the thalamus from the thalamus to the primary auditory cortex in the temporal lobe
Pathway of balance and equilibrium
Nerves traveling from the vestibule join together with nerves from the cochlear to form the vestibulocochlear nerve (auditory) where they travel to the cerebellum and vestibular nuclear complex. The cerebellum, vestibular nuclear complex, and reticular nuclei communicate between each other. The nerves then travel from the vestibular nuclear complex to both oculomotor control via cranial nerves III, IV, and VI (eye movements) and to spinal motor control via cranial nerve XI and vestibulospinal tracts (neck movements).
Disorders of the ear
Ottis media – inflammation of the middle ear
Myringotomy – the lancing of the eardrum to reduce pressure
Chapter 16 Endocrine System
Know Figure 16.1
Hormone – “to arouse” are proteins that act as chemical messengers in the blood
Tropic hormone – is a hormone which directly activates another gland to secrete another hormone
Know the different glands
Know the histology image of the glands and identify the various cell types that make up the gland
Know the hormones each gland secretes and which cell secretes them. In addition, know what happens when there is a hypersecretion or hyposecretion of the hormone
Info may be found in Tables 16.1, 16.2, 16.3, and 16.4 and Figures 16.9 and 16.14