Midterm Review

A&P Lab II

Divisions of Peripheral Nervous System

Afferent - Sensory Division:Afferent - Sensory Division:• Picks up sensory information and delivers it to the CNS.Picks up sensory information and delivers it to the CNS.

Efferent - Motor Division:Efferent - Motor Division:• Carries information to muscles and glands.Carries information to muscles and glands.

Two Divisions of the Efferent System:Two Divisions of the Efferent System: Somatic Somatic – (VOLUNTARY) carries information from CNS to – (VOLUNTARY) carries information from CNS to skeletal muscleskeletal muscle

AutonomicAutonomic – (INVOLUNTARY) carries information from CNS – (INVOLUNTARY) carries information from CNS to smooth muscle, cardiac muscle, and glandsto smooth muscle, cardiac muscle, and glands

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NEURON STRUCTURENEURON STRUCTURE

• DENDRITES- DENDRITES- multiple short branching processes that multiple short branching processes that extend from the cell body; receive signals from other extend from the cell body; receive signals from other cells and pass those signals to the cell bodycells and pass those signals to the cell body

• CELL BODYCELL BODY (SOMA, PERIKARYON) – centrally located; (SOMA, PERIKARYON) – centrally located; contains typical organelles and contain Nissl bodies contains typical organelles and contain Nissl bodies (scattered in the cytoplasm and contain Rough (scattered in the cytoplasm and contain Rough Endoplasmic ReticulumEndoplasmic Reticulum

• AXON – AXON – single extension from the cell body; transmits an single extension from the cell body; transmits an action potential to effectoraction potential to effector

Structures Associated with the Axon

• 1. Axon Collateral – branch of main axon; assists in cell firing

• 2. Axon Hillock – connection between the cell body and the axon; exact location where an impulse is generated

• 3. Nodes of Ranvier – gaps in the myelin shealth of the axon; help spread impulses more effienciently

• 4. Synaptic End Knob (Bulb) – contains a vesicle which houses a chemical called a neurotransmitter

THE MYELIN SHEATH: Insulating Material for Some THE MYELIN SHEATH: Insulating Material for Some AxonsAxons

• The myelin sheath is produced by the Schwann cell and The myelin sheath is produced by the Schwann cell and oligodendrocytesoligodendrocytes

•There are There are two determining factors that make up the speed of conductiontwo determining factors that make up the speed of conduction of of an action potential down an axon. First is the diameter, larger diameter = an action potential down an axon. First is the diameter, larger diameter = higher conduction velocity and higher conduction velocity and vice versa.vice versa. Second is the presence, or lack Second is the presence, or lack thereof, of the myelin sheath. A myelinated axon conducts a nerve impulse thereof, of the myelin sheath. A myelinated axon conducts a nerve impulse much faster than an unmyelinated axon.much faster than an unmyelinated axon.

• Myelin sheaths are comprised of unique proteins (myelins) and Myelin sheaths are comprised of unique proteins (myelins) and phospholipids.phospholipids.

•Give the axons a white appearance, thus neuron that have axons Give the axons a white appearance, thus neuron that have axons covered with covered with myelinmyelin make up the make up the white matter white matter within the cerebellum within the cerebellum and cerebrumand cerebrum

Neuroglial Cells

Schwann CellsSchwann Cellsform myelin around axons form myelin around axons in the in the PNSPNS

OligodendrocytesOligodendrocytesform myelin around the form myelin around the axons in the axons in the CNSCNS

AstrocytesAstrocytesregulate fluid composition regulate fluid composition around the neurons, bind blood around the neurons, bind blood vessels to nerves; play a role in vessels to nerves; play a role in the blood brain barrierthe blood brain barrier

MicrogliaMicroglia phagocytotic in response phagocytotic in response to inflammationto inflammation

Ependymal CellsEpendymal Cells play an active role inplay an active role in the formation and circulation the formation and circulation of of CSFCSF

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Satellite CellsSatellite CellsSupport ganglia in the PNSSupport ganglia in the PNS

MENINGES

Meninges• membranes surrounding CNS• protect CNS• three layers

• dura mater • arachnoid • pia mater

The cerebellum acts as a relay center for motor pathways and coordinates skeletal muscle coordination and balance.

Pia Mater

CerebrumDivided into 4 surface lobes and one inner lobe:

- Frontal lobes (2)

- Parietal lobes (2)

- Temporal lobes (2)

- Occipital lobes (2)

- Insular lobes (2)

• Has a Right and Left Hemisphere (Brain Lateralization)

• The hemispheres are connected by the corpus collosum –

A white nerve tract that runs transversely and facilitates communication between the cerebral hemispheres.

Structure of Cerebrum

• Corpus Callosum• connects hemispheres

• Convolutions • bumps or gyri

• Sulci• grooves

• Longitudinal fissure• separates hemispheres

• Transverse fissure• separates cerebrum from cerebellum

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Frontal Lobe

Parietal Lobe

Temporal Lobe

Occipital Lobe

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Functional Regions of Cerebral Cortex

Cerebral Cortex – thin layer of gray matter that constitutes the outermost portion of cerebrum; contains 75% of all neurons in nervous system

Lobes of Cerebrum

• Frontal• Parietal• Temporal• Occipital• Insula

• Epithalamus• Contains Pineal Gland – secretes melatonin/seratonin in the

absense and presence of light to help regulate sleep – wake patterns and assists it the regulation of the bodies rhythms.

Brain Stem

Three Parts1. Midbrain2. Pons3. Medulla Oblongata

Pons

• rounded bulge on underside of brainstem• between medulla oblongata and midbrain• helps regulate rate and depth of breathing (Pneumotaxic & Apneustic Areas)• relays nerve impulses to and from medulla oblongata and cerebellum

Medulla Oblongata

• enlarged continuation of spinal cord• conducts ascending and descending impulses between brain and spinal cord• contains cardiac, vasomotor, and respiratory control centers• contains various non-vital reflex control centers (coughing, sneezing, vomiting)

Ventricles• interconnected cavities• within cerebral hemispheres and brain stem• continuous with central canal of spinal cord• filled with cerebrospinal fluid (CSF)

• Lateral ventricles• Third ventricle• Fourth ventricle• Cerebral Aqueduct

4th Ventricle

Cerebral Aquaduct

Cerebrospinal Fluid

• secreted by choroid plexus• circulates in ventricles, central canal of spinal cord, and subarachnoid space• completely surrounds brain and spinal cord• clear liquid• nutritive and protective• helps maintain stable ion concentrations in CNS

Cranial Nerves I and II

Olfactory (I)• sensory• fibers transmit impulses associated with smell

Optic (II)• sensory• fibers transmit impulses associated with vision

Cranial Nerves III and IV

Trochlear (IV)• primarily motor• motor impulses to muscles that move the eyes

Oculomotor (III)• primarily motor• motor impulses to muscles that

• raise eyelids• move the eyes• focus lens•adjust light entering eye

Cranial Nerve VTrigeminal (V)

• mixed• opthalmic division

• sensory from surface of eyes, tear glands, scalp, forehead, and upper eyelids

• maxillary division• sensory from upper teeth, upper gum, upper lip, palate, and skin of face

• mandibular division• sensory from scalp, skin of jaw, lower teeth, lower gum, and lower lip• motor to muscles of mastication and muscles in floor of mouth

Cranial Nerves VI and VIIAbducens (VI)

• primarily motor• motor impulses to muscles that move the eyes

Facial (VII)• mixed• proprioception• sensory from taste receptors• motor to muscles of facial expression, tear glands, and salivary glands

Cranial Nerves VIII and IX

Vestibulocochlear (VIII)• sensory• sensory from equilibrium receptors of ear• sensory from hearing receptors

Glossopharyngeal (IX)• mixed• sensory from pharynx, tonsils, tongue, and carotid arteries• motor to salivary glands and muscles of pharynx

Cranial Nerve X

Vagus (X)• mixed• somatic motor to muscles of speech and swallowing• autonomic motor to viscera of thorax and abdomen• sensory from pharynx, larynx, esophagus, and viscera of thorax and abdomen

Cranial Nerves XI and XII

Accessory (XI)• primarily motor• motor to muscles of soft palate, pharynx, larynx, neck, and back

Hypoglossal (XII)• primarily motor• motor to muscles of the tongue

Cross Section of Spinal Cord

Cranial Nerves

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Spinal Cord Structure• Extends foramen magnum to 2nd lumbar vertebra

Structure of the Eye

• HollowHollow• SpheroidalSpheroidal• Wall has 3 layers (tunicsWall has 3 layers (tunics):):

• Outer - fibrous tunicOuter - fibrous tunic• Middle - vascular tunicMiddle - vascular tunic• Inner - nervous tunicInner - nervous tunic

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THE EYE: BASIC STRUCTURETHE EYE: BASIC STRUCTURE• Three tunics:Three tunics: (from external to internal): (from external to internal):

- Sclera (Outer Layer)- Sclera (Outer Layer)

- Choroid (Middle Layer)- Choroid (Middle Layer)

- Retina (Inner Layer)- Retina (Inner Layer)

Sclera:Sclera: Fibrocollagenous tissue that is modified Fibrocollagenous tissue that is modified anteriorly to form the cornea (transparent). The anteriorly to form the cornea (transparent). The cornea cornea covers 1/6 of the external eye, the covers 1/6 of the external eye, the remaining 5/6 is remaining 5/6 is covered by the sclera.covered by the sclera.

• Choroid:Choroid: A highly vascularized connective tissue A highly vascularized connective tissue layer which contains numerous layer which contains numerous melanocytesmelanocytes anteriorly and is continuous with the iris and anteriorly and is continuous with the iris and ciliary body.ciliary body.

THE CHOROID LAYERTHE CHOROID LAYER

• The Ciliary Body:The Ciliary Body:

- Is attached to the lens via the suspensory ligament.- Is attached to the lens via the suspensory ligament.

- The ciliary body contains smooth muscle cells. It is - The ciliary body contains smooth muscle cells. It is the the contraction-relaxationcontraction-relaxation of the ciliary muscles that of the ciliary muscles that focuses light on the retina via the bending of the lensfocuses light on the retina via the bending of the lens..

- The muscles are attached to the suspensory ligament - The muscles are attached to the suspensory ligament which is attached to the lens.which is attached to the lens.

THE THE RETINARETINA::• Anteriorly, it contributes to the ciliary body and the sclera Anteriorly, it contributes to the ciliary body and the sclera

• Posteriorly, contains the Posteriorly, contains the photoreceptors (rods & conesphotoreceptors (rods & cones), a ), a pigmented layer and many nerve cells and glial cells.pigmented layer and many nerve cells and glial cells.

• The rods and cones are mixed throughout the posterior retina.The rods and cones are mixed throughout the posterior retina.

• There are more There are more rods (for “night vision”)rods (for “night vision”) on the periphery. on the periphery.

• The highest concentration of The highest concentration of cones (color visioncones (color vision) is in the ) is in the center of the retina.center of the retina.

• Fovea centralisFovea centralis – Area in the center of the retina where only – Area in the center of the retina where only cones are presentcones are present = Where our best color images occur. = Where our best color images occur.

• Each cell contains a pigmented protein which contains Each cell contains a pigmented protein which contains retinalretinal (a (a derivative of Vitamin A).derivative of Vitamin A).

Visual Receptors

RODS-(DIMLIGHT RECEPTORS):RODS-(DIMLIGHT RECEPTORS):• Long, thin projectionsLong, thin projections• Contain light sensitive pigment Contain light sensitive pigment called rhodopsincalled rhodopsin• Hundred times more sensitive to Hundred times more sensitive to light than coneslight than cones• Provide vision in dim lightProvide vision in dim light• Produce colorless visionProduce colorless vision• Produce outlines of objectsProduce outlines of objects

CONES-(BRIGHT LIGHT CONES-(BRIGHT LIGHT RECEPTORS - COLOR RECEPTORS - COLOR VISION):VISION):

• Short, blunt projectionsShort, blunt projections• Contain light sensitive Contain light sensitive pigments called erythrolabe, pigments called erythrolabe,

chlorolabe, and chlorolabe, and cyanolabe,cyanolabe,• Provide vision in bright lightProvide vision in bright light• Produce sharp imagesProduce sharp images• Produce color visionProduce color vision

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PHOTORECEPTORSPHOTORECEPTORS

STRUCTURE OF THE STRUCTURE OF THE ANTERIOR HUMAN EYE.ANTERIOR HUMAN EYE.

Aqueous Humor

• Fluid in anterior cavity of eyeFluid in anterior cavity of eye• Secreted by epithelium on inner surface of the ciliary bodySecreted by epithelium on inner surface of the ciliary body• Provides nutrients for the eyeProvides nutrients for the eye• Maintains shape of anterior portion of eyeMaintains shape of anterior portion of eye• Leaves cavity through Leaves cavity through canal of Sclemmcanal of Sclemm (Glaucoma) (Glaucoma)

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Ciliary Body

• Forms internal ring around front of eyeForms internal ring around front of eye• Ciliary processesCiliary processes – radiating folds – radiating folds• Ciliary musclesCiliary muscles – contract and relax to move lens – contract and relax to move lens

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Iris

• Composed of connective tissue Composed of connective tissue and smooth muscleand smooth muscle

• Pupil is a hole in irisPupil is a hole in iris

• Dim light stimulates radial Dim light stimulates radial muscles and pupil dilatesmuscles and pupil dilates

• Bright light stimulates circular Bright light stimulates circular muscles and pupil constrictsmuscles and pupil constricts

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The “colored part” of the eye.The “colored part” of the eye.

Structure of the Ear:Structure of the Ear:• Composed of three major regions:Composed of three major regions:

- External ear- External ear

- Middle ear- Middle ear

- Inner ear- Inner ear

• The The external earexternal ear consists of the consists of the pinna pinna (auricle(auricle) and the ) and the external auditory canal external auditory canal (meatus(meatus).).

• The middle earThe middle ear consists of the consists of the tympanic tympanic membrane (eardrum)membrane (eardrum) and and three auditory three auditory ossiclesossicles (bones). These are the (bones). These are the malleus, malleus, incus, and stapesincus, and stapes (or hammer, anvil and (or hammer, anvil and stirrup). The middle ear also consists of the stirrup). The middle ear also consists of the Eustachian (auditory) tube.Eustachian (auditory) tube.

Structure Continued:• The The inner earinner ear consists of the consists of the vestibular vestibular ((balance) apparatusbalance) apparatus

and the auditory and the auditory apparatus.apparatus.

The vestibular apparatusThe vestibular apparatus – Three – Three semicircular ductssemicircular ducts, the , the utricleutricle and the and the saccule.saccule. The saccule consists of the The saccule consists of the cochlear duct and the Organ of Corticochlear duct and the Organ of Corti (the auditory (the auditory apparatus)apparatus)

• The inner ear lies within the portion of the temporal bone The inner ear lies within the portion of the temporal bone known as the known as the osseous labyrinthosseous labyrinth.. The osseous labyrinth The osseous labyrinth contains perilymph (plasma like fluid)contains perilymph (plasma like fluid)

Inner Ear - ComponentsInner Ear - Components• The osseous labyrinth contains the membranous The osseous labyrinth contains the membranous labyrinth which is composed of fluid-filled sacs and ducts:labyrinth which is composed of fluid-filled sacs and ducts:

- Semicircular canals- Semicircular canals

- Saccule- Saccule

- Utricle- Utricle

- Cochlear duct- Cochlear duct

- - Endolymphatic sac and ductEndolymphatic sac and duct

• The membranous labyrinth is surrounded by the osseous The membranous labyrinth is surrounded by the osseous labyrinth which contains the perilymphlabyrinth which contains the perilymph (like CSF or (like CSF or plasma, contains sodium).plasma, contains sodium).

• The membranous labyrinth contains specialized The membranous labyrinth contains specialized epithelial cells for sound perceptionepithelial cells for sound perception..

Inner Ear

Complex system of labyrinthsComplex system of labyrinths

• Osseous labyrinth:Osseous labyrinth: • bony canal in temporal bony canal in temporal bonebone• filled with perilymph. filled with perilymph.

• Membranous labyrinth:Membranous labyrinth:• tube within osseous tube within osseous labyrinthlabyrinth• filled with endolymph.filled with endolymph.

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Inner Ear

3 Parts of Labyrinths:3 Parts of Labyrinths:

• CochleaCochlea• functions in hearingfunctions in hearing

• Semicircular canalsSemicircular canals• function in function in equilibriumequilibrium

• VestibuleVestibule• functions in functions in equilibriumequilibrium

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External Ear• AURICLEAURICLE

• Collects sound waves.Collects sound waves.• EXTERNAL AUDITORYEXTERNAL AUDITORY MEATUSMEATUS

• Lined with ceruminous Lined with ceruminous glandsglands• Carries sound to tympanic Carries sound to tympanic membranemembrane• Terminates with tympanic Terminates with tympanic membrane.membrane.

• TYMPANIC MEMBRANETYMPANIC MEMBRANE• Vibrates in response Vibrates in response to to sound waves.sound waves.

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Auditory Tube (Eustachian Tube)

• EUSTACHIAN TUBEEUSTACHIAN TUBE• Connects middle ear Connects middle ear to throatto throat• Helps maintain equal Helps maintain equal pressure on both sides pressure on both sides of tympanic membraneof tympanic membrane• Usually closed by Usually closed by valve-like flaps in valve-like flaps in throatthroat

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So How does sound get to our brain?So How does sound get to our brain?• It is funneled by the acoustics of the It is funneled by the acoustics of the pinnapinna into the into the external meatusexternal meatus (external auditory canal). (external auditory canal).

• To the To the tympanic membranetympanic membrane

• To the To the malleus malleus (attached to the eardrum), (attached to the eardrum), incus incus and and stapesstapes where the stapes vibrates in the oval window. The where the stapes vibrates in the oval window. The ossiclesossicles function in amplification of sound. The vibrations on the function in amplification of sound. The vibrations on the oval window causes pressure waves in the endolymph & oval window causes pressure waves in the endolymph & perilymph (fluids of the cochlea). perilymph (fluids of the cochlea).

• The pressure waves in the endolymph cause vibration of The pressure waves in the endolymph cause vibration of the basilar membrane (a thin membrane extending the basilar membrane (a thin membrane extending throughout the length of the cochlea).throughout the length of the cochlea).

• The basilar membrane is covered with cells with The basilar membrane is covered with cells with mechanoreceptors known as hair cells. mechanoreceptors known as hair cells.

On the apical border of hair cells, cilia are found. When the On the apical border of hair cells, cilia are found. When the basilar membrane moves the cilia make contact with the tectoral basilar membrane moves the cilia make contact with the tectoral

membrane (the roof) and the displacement of the cilia (hairs) membrane (the roof) and the displacement of the cilia (hairs) opens ion channels. This results in NT exocytosis. opens ion channels. This results in NT exocytosis.

• Dendrites from bipolar auditory afferent neurons are Dendrites from bipolar auditory afferent neurons are stimulated by this NT, and thus sound vibrations are converted stimulated by this NT, and thus sound vibrations are converted into a nerve impulse.into a nerve impulse.

Balance:Balance:• The semicircular canals are three tubes filled with endolymphThe semicircular canals are three tubes filled with endolymph

• Like the cochlea, they contain hair cells that detect motion, but Like the cochlea, they contain hair cells that detect motion, but rather than sound, rotational acceleration is perceived. rather than sound, rotational acceleration is perceived.

• They are innervated by afferent fibers which transmit the They are innervated by afferent fibers which transmit the signal to the pons and cerebellum.signal to the pons and cerebellum.

• The uThe utricle tricle and and sacculesaccule are two other balance-monitoring are two other balance-monitoring organs located in the inner ear. They monitor static equilibrium organs located in the inner ear. They monitor static equilibrium and linear acceleration.and linear acceleration.

The Endocrine System - General FactsThe Endocrine System - General Facts• Body’s Secondary Control System Body’s Secondary Control System

• Major function is maintaining homeostasisMajor function is maintaining homeostasis

• This is achieved by feedback loops (mostly negative or This is achieved by feedback loops (mostly negative or inhibitory feedback loops).inhibitory feedback loops).

• Today, Three endocrine systems are recognized:Today, Three endocrine systems are recognized:

• The General Endocrine System (Thyroid Gland, The General Endocrine System (Thyroid Gland, Adrenal Glands, Parathyroid)Adrenal Glands, Parathyroid)

• The Neuroendocrine System (Hypothalamus, Pituitary) The Neuroendocrine System (Hypothalamus, Pituitary)

• The diffuse endocrine system (endocrine tissue – The diffuse endocrine system (endocrine tissue – Thymus, Pancreas, Kidneys, Heart, Skin)Thymus, Pancreas, Kidneys, Heart, Skin)

Anterior Pituitary Gland:Anterior Pituitary Gland:

•The APG synthesizes and secretes many protein hormones (non-steroidal) in The APG synthesizes and secretes many protein hormones (non-steroidal) in response to the commands from the hypothalamus (response to the commands from the hypothalamus (Controlled by the Controlled by the hypothalamus and the releasing factors):hypothalamus and the releasing factors):

1.Thyroid Stimulating hormone (TSH)2. Adrenocorticotropic hormone (ACTH) 3. Follicle Stimulating hormone (FSH)4. Luteinizing hormone (LH)5. Prolactin (PRL)6. Growth hormone (GH) 7. Melanocyte-stimulating hormone (MSH)

•The TSH, ACTH, FSH, GH and LH hormones are tropic hormones that simulate other endocrine glands. In response, the other endocrine glands produce hormones that affect metabolism. For example, TSH from the pituitary gland stimulates the thyroid gland to produce thyroid hormones. In turn, thyroid hormones inhibit the release of calcium in the blood.

Posterior Pituitary Gland:Posterior Pituitary Gland:

• Does not synthesize any hormonesDoes not synthesize any hormones

• It only stores the hormones that are synthesized in the It only stores the hormones that are synthesized in the hypothalamushypothalamus

•Neuron cell bodies of the hypothalamus produce Neuron cell bodies of the hypothalamus produce two hormonestwo hormones

1. 1. Antidiuretic hormone (ADH)Antidiuretic hormone (ADH)2. Oxytocin2. Oxytocin

•These are transported by axons to the neurohypophysis where These are transported by axons to the neurohypophysis where they are stored (Herring Bodies).they are stored (Herring Bodies).•The hormones are released by neurosecretion.The hormones are released by neurosecretion.

•The hormones travel down the axons of the hypothalamus and The hormones travel down the axons of the hypothalamus and terminate in the PPG where hormones are stored until released terminate in the PPG where hormones are stored until released (secreted).(secreted).

Anterior Pituitary HormonesGrowth Hormone (GH):Growth Hormone (GH):

• stimulates increase in size and rate of body cellsstimulates increase in size and rate of body cells• enhances movement of amino acids through membranes enhances movement of amino acids through membranes (increased protein synthesis)(increased protein synthesis)• promotes growth of long bonespromotes growth of long bones• secretion stimulated by growth hormone-releasing secretion stimulated by growth hormone-releasing hormonehormone

Prolactin (PRL):Prolactin (PRL):• sustains milk production after birthsustains milk production after birth• amplifies effect of LH in malesamplifies effect of LH in males• secretion inhibited by prolactin releasing hormone.secretion inhibited by prolactin releasing hormone.

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Anterior Pituitary Hormones

Thyroid Stimulating Hormone (TSH):Thyroid Stimulating Hormone (TSH):• controls secretions of hormones from the thyroid glandcontrols secretions of hormones from the thyroid gland• controlled by thyrotropin-releasing hormone.controlled by thyrotropin-releasing hormone.

Adrenocorticotropic Hormone (ACTH):Adrenocorticotropic Hormone (ACTH):• controls secretions of some hormones of adrenal cortexcontrols secretions of some hormones of adrenal cortex• controlled by corticotropin-releasing hormone.controlled by corticotropin-releasing hormone.

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Anterior Pituitary Hormones

Follicle-Stimulating Hormone (FSH):Follicle-Stimulating Hormone (FSH):• stimulates development of egg-containing follicles in stimulates development of egg-containing follicles in ovariesovaries• stimulates follicular cells to secrete estrogenstimulates follicular cells to secrete estrogen• stimulates production of sperm cellsstimulates production of sperm cells• controlled by gonadotropin-releasing hormone.controlled by gonadotropin-releasing hormone.

Luteinizing Hormone (LH)Luteinizing Hormone (LH)• promotes secretions of sex hormonespromotes secretions of sex hormones• stimulates release of egg from ovarystimulates release of egg from ovary• promotes growth of long bonespromotes growth of long bones• controlled by gonadotropin-releasing hormone.controlled by gonadotropin-releasing hormone. 13-19

Posterior Pituitary Hormones

Antidiuretic Hormone (ADH):Antidiuretic Hormone (ADH):• causes kidneys to reduce water excretioncauses kidneys to reduce water excretion• in high concentration, raises blood pressure (vasopressin)in high concentration, raises blood pressure (vasopressin)• controlled by hypothalamus in response to changes in controlled by hypothalamus in response to changes in blood water concentration and blood volume.blood water concentration and blood volume.

Oxytocin (OT):Oxytocin (OT):• stimulates uterine contractionsstimulates uterine contractions• stimulates mammary glands to release milkstimulates mammary glands to release milk• controlled by hypothalamus in response to stretch in controlled by hypothalamus in response to stretch in uterine and vaginal walls and stimulation of breasts.uterine and vaginal walls and stimulation of breasts.

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REMEMBER, THESE TWO HORMONES ARE SYNTHESIZED INREMEMBER, THESE TWO HORMONES ARE SYNTHESIZED INTHE HYPOTHALAMUS, PASSED TO THE NEUROHYPOPHYSIS, THE HYPOTHALAMUS, PASSED TO THE NEUROHYPOPHYSIS,

WHERE THEY ARE STORED PRIOR TO SECRETION.WHERE THEY ARE STORED PRIOR TO SECRETION.

Thyroid Gland HormonesThyroxine (TThyroxine (T44) and Triiodothyronine (T) and Triiodothyronine (T33):):

• increases rate of energy release from carbohydratesincreases rate of energy release from carbohydrates• increases rate of protein synthesisincreases rate of protein synthesis• accelerates growthaccelerates growth• stimulates activity in the nervous systemstimulates activity in the nervous system• controlled by TSH (From the Anterior Pituitary).controlled by TSH (From the Anterior Pituitary).

Calcitonin:Calcitonin:• lowers blood calciumlowers blood calcium and phosphate ion concentrations and phosphate ion concentrations by inhibiting the release of calcium and phosphate from by inhibiting the release of calcium and phosphate from bones and increases the rate at which the kidney excrete bones and increases the rate at which the kidney excrete calciumcalcium• increases rate at which calcium and phosphate are increases rate at which calcium and phosphate are deposited in bonesdeposited in bones 13-22

Parathyroid Hormone

• PTH:PTH:• increases blood calcium levelsincreases blood calcium levels• decreases blood phosphate levelsdecreases blood phosphate levels• stimulates bone resorption (boen removal) by osteoclastsstimulates bone resorption (boen removal) by osteoclasts• inhibits osteoblastsinhibits osteoblasts• stimulates kidneys to retain calcium and excrete phosphatestimulates kidneys to retain calcium and excrete phosphate• promotes calcium absorption into intestinepromotes calcium absorption into intestine

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WITH CALCITONIN, PARATHYROID HORMONE HELPS TO REGULATEWITH CALCITONIN, PARATHYROID HORMONE HELPS TO REGULATECALCIUM HOMEOSTASISCALCIUM HOMEOSTASIS..

THE PANCREASTHE PANCREAS

BOTH AN EXOCRINE AND ANBOTH AN EXOCRINE AND ANENDOCRINE GLANDENDOCRINE GLAND

Pancreatic Hormones

Glucagon: Glucagon: • secreted by alpha cells of pancreatic isletssecreted by alpha cells of pancreatic islets• stimulates liver to break down glycogenstimulates liver to break down glycogen• stimulates liver to convert non-carbohydrates into glucosestimulates liver to convert non-carbohydrates into glucose• stimulates break down of fatsstimulates break down of fats• controlled by blood glucose concentrationscontrolled by blood glucose concentrations

Somatostatin:Somatostatin:• secreted by delta cells of pancreatic isletssecreted by delta cells of pancreatic islets• helps regulate carbohydrateshelps regulate carbohydrates• Inhibits the secretions of Alpha and Beta CellsInhibits the secretions of Alpha and Beta Cells

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Pancreatic Hormones

Insulin:Insulin:• secreted by beta cells of pancreatic isletssecreted by beta cells of pancreatic islets• promotes formation of glycogen from glucosepromotes formation of glycogen from glucose• inhibits conversion of non-carbohydrates into glucoseinhibits conversion of non-carbohydrates into glucose• enhances movement of glucose into adipose and muscle cellsenhances movement of glucose into adipose and muscle cells• decreases blood glucose concentrationsdecreases blood glucose concentrations• promotes transport of amino acidspromotes transport of amino acids• enhances synthesis of proteins and fatsenhances synthesis of proteins and fats• controlled by blood glucose concentrationscontrolled by blood glucose concentrations

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Insulin and Glucagon

Insulin and glucagon function together to Insulin and glucagon function together to stabilize blood glucose concentrationsstabilize blood glucose concentrations

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THE ADRENAL GLANDS• Lies on the superior pole of the kidney.Lies on the superior pole of the kidney.

• The adrenal glands, small organs near the kidneyThe adrenal glands, small organs near the kidney..

• Is subdivided into two glands:Is subdivided into two glands:

- Adrenal Medulla (inside)- Adrenal Medulla (inside)

- Adrenal Cortex (outside)- Adrenal Cortex (outside)

Adrenal Adrenal GlandGland

HORMONES OF THE HORMONES OF THE ADRENALADRENALCORTEXCORTEX

ZONA GLOMERULOSAZONA GLOMERULOSA (OUTER LAYER): (OUTER LAYER):MINERALOCORTICOIDS: MINERALOCORTICOIDS: ALDOSTERONEALDOSTERONE

ZONA FASCICULATAZONA FASCICULATA (MIDDLE LAYER): (MIDDLE LAYER):GLUCOCORTICOIDS: GLUCOCORTICOIDS: CORISONE, CORTISOLCORISONE, CORTISOLHYDROCORTISONE, CORTICOSTERONEHYDROCORTISONE, CORTICOSTERONE

ZONA RETICULARISZONA RETICULARIS (INNER LAYER): (INNER LAYER):ANDROGENS: ANDROGENS: TESTOSTERONE.TESTOSTERONE.

Adrenal Cortex Hormones

Aldosterone:Aldosterone:• increases blood volume and pressure by promoting increases blood volume and pressure by promoting conservation of sodium ions and water.conservation of sodium ions and water.

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Adrenal Cortex HormonesCortisol:Cortisol:

• decreases protein synthesisdecreases protein synthesis• increases fatty acid releaseincreases fatty acid release• stimulates glucose synthesis from noncarbohydratesstimulates glucose synthesis from noncarbohydrates

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HORMONES OF THE HORMONES OF THE ADRENAL ADRENAL MEDULLAMEDULLA

• EPINEPHRINE (ADRENALIN)EPINEPHRINE (ADRENALIN)• NOREPINEPHRINE (NORADRENALIN)NOREPINEPHRINE (NORADRENALIN)

Actions of Steroid Hormones

• Hormone crosses membranes.Hormone crosses membranes.

• Hormone combines with Hormone combines with receptor in nucleusreceptor in nucleus

• Synthesis of mRNA Synthesis of mRNA activatedactivated

• mRNA enters cytoplasm to mRNA enters cytoplasm to direct synthesis of a new proteindirect synthesis of a new protein

13-8MECHANISM OF ACTION OF STEROID HORMONES.MECHANISM OF ACTION OF STEROID HORMONES.

Actions of Nonsteroid Hormones

• Adenylate cyclase activated

• Hormone binds to receptor on cell membrane

• ATP converted to cAMPATP converted to cAMP

• cAMP promotes a series of reactions leading to cellular changes

13-9MECHANISMS OF ACTION OF NONSTEROID HORMONES.MECHANISMS OF ACTION OF NONSTEROID HORMONES.