Download 16-2 The Sympathetic Division

Exam 1 Study guide
An Introduction to the ANS and Higher-Order Functions
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Somatic Nervous System (SNS)
o Operates under conscious control
o Seldom affects long-term survival
o SNS controls skeletal muscles
Autonomic Nervous System (ANS)
o Operates without conscious instruction
o ANS controls visceral effectors
o Coordinates system functions
 Cardiovascular, respiratory, digestive, urinary, reproductive
16-1 Autonomic Nervous System
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Organization of the ANS
o Integrative centers
 For autonomic activity in hypothalamus
 Neurons comparable to upper motor neurons in SNS
16-1 Autonomic Nervous System
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Organization of the ANS
o Visceral motor neurons
 In brain stem and spinal cord, are known as preganglionic neurons
 Preganglionic fibers
o Axons of preganglionic neurons
o Leave CNS and synapse on ganglionic neurons
16-1 Autonomic Nervous System
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Visceral Motor Neurons
o Autonomic ganglia
 Contain many ganglionic neurons
 Ganglionic neurons innervate visceral effectors
o Such as cardiac muscle, smooth muscle, glands, and adipose
tissue
 Postganglionic fibers
o Axons of ganglionic neurons
16-1 Divisions of the ANS
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The Autonomic Nervous System
o Operates largely outside our awareness
o Has two divisions
1. Sympathetic division
o Increases alertness, metabolic rate, and muscular abilities
2. Parasympathetic division
o Reduces metabolic rate and promotes digestion
16-1 Divisions of the ANS
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Sympathetic Division
o Kicks in only during exertion, stress, or emergency
o “Fight or flight”
Parasympathetic Division
o Controls during resting conditions
o “Rest and digest”
16-1 Divisions of the ANS
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Sympathetic and Parasympathetic Division
1. Most often, these two divisions have opposing effects
 If the sympathetic division causes excitation, the parasympathetic
causes inhibition
2. The two divisions may also work independently
 Only one division innervates some structures
3. The two divisions may work together, with each controlling one stage of a
complex process
16-1 Divisions of the ANS
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Sympathetic Division
o Preganglionic fibers (thoracic and superior lumbar; thoracolumbar)
synapse in ganglia near spinal cord
o Preganglionic fibers are short
o Postganglionic fibers are long
o Prepares body for crisis, producing a “fight or flight” response
 Stimulates tissue metabolism
 Increases alertness
16-1 Divisions of the ANS
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Seven Responses to Increased Sympathetic Activity
1. Heightened mental alertness
2. Increased metabolic rate
3. Reduced digestive and urinary functions
4. Energy reserves activated
5. Increased respiratory rate and respiratory passageways dilate
6. Increased heart rate and blood pressure
7. Sweat glands activated
16-1 Divisions of the ANS
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Parasympathetic Division
o Preganglionic fibers originate in brain stem and sacral segments of spinal
cord; craniosacral
o Synapse in ganglia close to (or within) target organs
o Preganglionic fibers are long
o Postganglionic fibers are short
o Parasympathetic division stimulates visceral activity
o Conserves energy and promotes sedentary activities
o
16-1 Divisions of the ANS
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Five Responses to Increased Parasympathetic Activity
1. Decreased metabolic rate
2. Decreased heart rate and blood pressure
3. Increased secretion by salivary and digestive glands
4. Increased motility and blood flow in digestive tract
5. Urination and defecation stimulation
16-1 Divisions of the ANS
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Enteric Nervous System (ENS)
o Third division of ANS
o Extensive network in digestive tract walls
o Complex visceral reflexes coordinated locally
o Roughly 100 million neurons
o All neurotransmitters are found in the brain
16-2 The Sympathetic Division
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The Sympathetic Division
o Preganglionic neurons located between segments T 1 and L2 of spinal cord
o Ganglionic neurons in ganglia near vertebral column
o Cell bodies of preganglionic neurons in lateral gray horns
o Axons enter ventral roots of segments
16-2 The Sympathetic Division
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Ganglionic Neurons
o Occur in three locations
1. Sympathetic chain ganglia
2. Collateral ganglia
3. Adrenal medullae
16-2 The Sympathetic Division
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Sympathetic Chain Ganglia
o On both sides of vertebral column
o Control effectors:
 In body wall
 Inside thoracic cavity
 In head
 In limbs
16-2 The Sympathetic Division
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Collateral Ganglia
o Are anterior to vertebral bodies
o Contain ganglionic neurons that innervate tissues and organs in
abdominopelvic cavity
16-2 The Sympathetic Division
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Adrenal Medullae (Suprarenal Medullae)
o Very short axons
o When stimulated, release neurotransmitters into bloodstream (not at
synapse)
o Function as hormones to affect target cells throughout body
16-2 The Sympathetic Division
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Fibers in Sympathetic Division
o Preganglionic fibers
 Are relatively short
 Ganglia located near spinal cord
o Postganglionic fibers
 Are relatively long, except at adrenal medullae
16-2 The Sympathetic Division
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Organization and Anatomy of the Sympathetic Division
o Ventral roots of spinal segments T1–L2 contain sympathetic preganglionic
fibers
 Give rise to myelinated white ramus
 Carry myelinated preganglionic fibers into sympathetic chain ganglion
 May synapse at collateral ganglia or in adrenal medullae
16-2 The Sympathetic Division
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Sympathetic Chain Ganglia
o Preganglionic fibers
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One preganglionic fiber synapses on many ganglionic neurons
Fibers interconnect sympathetic chain ganglia
Each ganglion innervates particular body segment(s)
16-2 The Sympathetic Division
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Sympathetic Chain Ganglia
o Postganglionic Fibers
 Paths of unmyelinated postganglionic fibers depend on targets
16-2 The Sympathetic Division
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Sympathetic Chain Ganglia
o Postganglionic fibers control visceral effectors
 In body wall, head, neck, or limbs
 Enter gray ramus
 Return to spinal nerve for distribution
o Postganglionic fibers innervate effectors
 Sweat glands of skin
 Smooth muscles in superficial blood vessels
16-2 The Sympathetic Division
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Sympathetic Chain Ganglia
o Postganglionic fibers innervating structures in thoracic cavity form bundles
 Sympathetic nerves
16-2 The Sympathetic Division
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Sympathetic Chain Ganglia
o Each sympathetic chain ganglia contains:
 3 cervical ganglia
 10–12 thoracic ganglia
 4–5 lumbar ganglia
 4–5 sacral ganglia
 1 coccygeal ganglion
16-2 The Sympathetic Division
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Sympathetic Chain Ganglia
o Preganglionic neurons
 Limited to spinal cord segments T1–L2
 White rami (myelinated preganglionic fibers)
 Innervate neurons in:
o Cervical, inferior lumbar, and sacral sympathetic chain ganglia
16-2 The Sympathetic Division
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Sympathetic Chain Ganglia
o Chain ganglia provide postganglionic fibers
 Through gray rami (unmyelinated postganglionic fibers)
 To cervical, lumbar, and sacral spinal nerves
16-2 The Sympathetic Division
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Sympathetic Chain Ganglia
o Only spinal nerves T1–L2 have white rami
o Every spinal nerve has gray ramus
 That carries sympathetic postganglionic fibers for distribution in body
wall
16-2 The Sympathetic Division
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Sympathetic Chain Ganglia
o Postganglionic sympathetic fibers
 In head and neck leave superior cervical sympathetic ganglia
 Supply the regions and structures innervated by cranial nerves III, VII,
IX, X
16-2 The Sympathetic Division
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Collateral Ganglia
o Receive sympathetic innervation via sympathetic preganglionic fibers
o Splanchnic nerves
 Formed by preganglionic fibers that innervate collateral ganglia
 In dorsal wall of abdominal cavity
 Originate as paired ganglia (left and right)
 Usually fuse together in adults
16-2 The Sympathetic Division
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Collateral Ganglia
o Postganglionic fibers
 Leave collateral ganglia
 Extend throughout abdominopelvic cavity
 Innervate variety of visceral tissues and organs
o Reduction of blood flow and energy by organs not vital to shortterm survival
o Release of stored energy reserves
16-2 The Sympathetic Division
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Collateral Ganglia
o Preganglionic fibers from seven inferior thoracic segments
 End at celiac ganglion or superior mesenteric ganglion
 Ganglia embedded in network of autonomic nerves
o Preganglionic fibers from lumbar segments
 Form splanchnic nerves
 End at inferior mesenteric ganglion
16-2 The Sympathetic Division
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Collateral Ganglia
o Celiac ganglion
 Pair of interconnected masses of gray matter
 May form single mass or many interwoven masses
 Postganglionic fibers innervate stomach, liver, gallbladder, pancreas,
and spleen
16-2 The Sympathetic Division
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Collateral Ganglia
o Superior mesenteric ganglion
 Near base of superior mesenteric artery
 Postganglionic fibers innervate small intestine and proximal 2/3 of
large intestine
16-2 The Sympathetic Division
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Collateral Ganglia
o Inferior mesenteric ganglion
 Near base of inferior mesenteric artery
 Postganglionic fibers provide sympathetic innervation to portions of:
o Large intestine
o Kidney
o Urinary bladder
o Sex organs
16-2 The Sympathetic Division
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Adrenal Medullae
o Preganglionic fibers entering adrenal gland proceed to center (adrenal
medulla)
o Modified sympathetic ganglion
o Preganglionic fibers synapse on neuroendocrine cells
o Specialized neurons secrete hormones into bloodstream
16-2 The Sympathetic Division
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Adrenal Medullae
o Neuroendocrine cells
 Secrete neurotransmitters epinephrine (E) and norepinephrine (NE)
 Epinephrine
o Also called adrenaline
o Is 75–80 percent of secretory output
 Remaining is norepinephrine (NE)
o Noradrenaline
16-2 The Sympathetic Division
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Adrenal Medullae
o Bloodstream carries neurotransmitters through body
o Causing changes in metabolic activities of different cells including cells not
innervated by sympathetic postganglionic fibers
o Effects last longer
 Hormones continue to diffuse out of bloodstream
16-2 The Sympathetic Division
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Sympathetic Activation
o Change activities of tissues and organs by:
 Releasing NE at peripheral synapses
o Target specific effectors, smooth muscle fibers in blood vessels of
skin
o Are activated in reflexes
o Do not involve other visceral effectors
16-2 The Sympathetic Division
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Sympathetic Activation
o Changes activities of tissues and organs by:
 Distributing E and NE throughout body in bloodstream
o Entire division responds (sympathetic activation)
o Are controlled by sympathetic centers in hypothalamus
o Effects are not limited to peripheral tissues
o Alters CNS activity
16-2 The Sympathetic Division
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Changes Caused by Sympathetic Activation
o Increased alertness
o Feelings of energy and euphoria
o Change in breathing
o Elevation in muscle tone
o Mobilization of energy reserves
16-4 The Parasympathetic Division
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Autonomic Nuclei
o Are contained in the mesencephalon, pons, and medulla oblongata
 Associated with cranial nerves III, VII, IX, X
In lateral gray horns of spinal segments S2–S4
o
16-4 The Parasympathetic Division
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Ganglionic Neurons in Peripheral Ganglia
o Terminal ganglion
 Near target organ
 Usually paired
o Intramural ganglion
 Embedded in tissues of target organ
 Interconnected masses
 Clusters of ganglion cells
16-4 The Parasympathetic Division
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Organization and Anatomy of the Parasympathetic Division
o Parasympathetic preganglionic fibers leave brain as components of cranial
nerves
 III (oculomotor)
 VII (facial)
 IX (glossopharyngeal)
 X (vagus)
o Parasympathetic preganglionic fibers leave spinal cord at sacral level
16-4 The Parasympathetic Division
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Oculomotor, Facial, and Glossopharyngeal Nerves
o Control visceral structures in head
o Synapse in ciliary, pterygopalatine, submandibular, and otic ganglia
o Short postganglionic fibers continue to their peripheral targets
16-4 The Parasympathetic Division
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Vagus Nerve
o Provides preganglionic parasympathetic innervation to structures in:
 Neck
 Thoracic and abdominopelvic cavities as distant as a distal portion of
large intestine
o Provides 75 percent of all parasympathetic outflow
o Branches intermingle with fibers of sympathetic division
16-4 The Parasympathetic Division
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Sacral Segments of Spinal Cord
o Preganglionic fibers carry sacral parasympathetic output
o Do not join ventral roots of spinal nerves, instead form pelvic nerves
 Pelvic nerves innervate intramural ganglia in walls of kidneys, urinary
bladder, portions of large intestine, and the sex organs
16-4 The Parasympathetic Division
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Parasympathetic Activation
o Centers on relaxation, food processing, and energy absorption
o Localized effects, last a few seconds at most
16-4 The Parasympathetic Division
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Major Effects of Parasympathetic Division
o Constriction of the pupils
 To restrict the amount of light that enters the eyes
 And focusing of the lenses of the eyes on nearby objects
o Secretion by digestive glands
 Including salivary glands, gastric glands, duodenal glands, intestinal
glands, the pancreas (exocrine and endocrine), and the liver
16-4 The Parasympathetic Division
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Major Effects of Parasympathetic Division
o Secretion of hormones
 That promote the absorption and utilization of nutrients by peripheral
cells
o Changes in blood flow and glandular activity
 Associated with sexual arousal
o Increase in smooth muscle activity
 Along the digestive tract
16-4 The Parasympathetic Division
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Major Effects of Parasympathetic Division
o Stimulation and coordination of defecation
o Contraction of the urinary bladder during urination
o Constriction of the respiratory passageways
o Reduction in heart rate and in the force of contraction
An Introduction to the Endocrine System
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The Endocrine System
o Regulates long-term processes
 Growth
 Development
 Reproduction
o Uses chemical messengers to relay information and instructions between
cells
18-1 Homeostasis and Intercellular Communication
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Direct Communication
o Exchange of ions and molecules between adjacent cells across gap
junctions
o Occurs between two cells of same type
o Highly specialized and relatively rare
Paracrine Communication
o Uses chemical signals to transfer information from cell to cell within single
tissue
o Most common form of intercellular communication
18-1 Homeostasis and Intercellular Communication
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Endocrine Communication
o Endocrine cells release chemicals (hormones) into bloodstream
o Alters metabolic activities of many tissues and organs simultaneously
18-1 Homeostasis and Intercellular Communication
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Target Cells
o Are specific cells that possess receptors needed to bind and “read”
hormonal messages
Hormones
o Stimulate synthesis of enzymes or structural proteins
o Increase or decrease rate of synthesis
o Turn existing enzyme or membrane channel “on” or “off”
18-1 Homeostasis and Intercellular Communication
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Synaptic Communication
o Ideal for crisis management
o Occurs across synaptic clefts
o Chemical message is “neurotransmitter”
o Limited to a very specific area
18-2 Hormones
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Classes of Hormones
o Hormones can be divided into three groups
1. Amino acid derivatives
2. Peptide hormones
3. Lipid derivatives
Secretion and Distribution of Hormones
o Hormones circulate freely or travel bound to special carrier proteins
18-3 The Pituitary Gland
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The Pituitary Gland
o Also called hypophysis
o Lies within sella turcica
 Sellar diaphragm
o A dural sheet that locks pituitary in position
o Isolates it from cranial cavity
o Hangs inferior to hypothalamus
 Connected by infundibulum
18-3 The Pituitary Gland
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The Pituitary Gland
o Releases nine important peptide hormones
o Hormones bind to membrane receptors
 Use cAMP as second messenger
18-3 The Pituitary Gland
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The Anterior Lobe of the Pituitary Gland
o Also called adenohypophysis
 Hormones “turn on” endocrine glands or support other organs
 Has three regions
1. Pars distalis
2. Pars tuberalis
3. Pars intermedia
18-3 The Pituitary Gland
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The Hypophyseal Portal System
o Median eminence
 Swelling near attachment of infundibulum
 Where hypothalamic neurons release regulatory factors
o Into interstitial fluids
o Through fenestrated capillaries
18-3 The Pituitary Gland
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Portal Vessels
o Blood vessels link two capillary networks
o Entire complex is portal system
 Ensures that regulatory factors reach intended target cells before
entering general circulation
18-3 The Pituitary Gland
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Hypothalamic Control of the Anterior Lobe
o Two classes of hypothalamic regulatory hormones
1. Releasing hormones (RH)
o Stimulate synthesis and secretion of one or more hormones at
anterior lobe
2. Inhibiting hormones (IH)
o Prevent synthesis and secretion of hormones from the anterior lobe
o Rate of secretion is controlled by negative feedback
18-3 The Pituitary Gland
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The Posterior Lobe of the Pituitary Gland
o Also called neurohypophysis
 Contains unmyelinated axons of hypothalamic neurons
 Supraoptic and paraventricular nuclei manufacture:
o Antidiuretic hormone (ADH)
o Oxytocin (OXT)
18-4 The Thyroid Gland
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The Thyroid Gland
o Lies inferior to thyroid cartilage of larynx
o Consists of two lobes connected by narrow isthmus
 Thyroid follicles
o Hollow spheres lined by cuboidal epithelium
o Cells surround follicle cavity that contains viscous colloid
o Surrounded by network of capillaries that:
Deliver nutrients and regulatory hormones
Accept secretory products and metabolic wastes
18-4 The Thyroid Gland
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Thyroglobulin (Globular Protein)
o Synthesized by follicle cells
o Secreted into colloid of thyroid follicles
o Molecules contain the amino acid tyrosine
Thyroxine (T4)
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o Also called tetraiodothyronine
o Contains four iodide ions
Triiodothyronine (T3)
o Contains three iodide ions
18-4 The Thyroid Gland
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Thyroid-binding Globulins (TBGs)
o Plasma proteins that bind about 75 percent of T4 and 70 percent of T3
entering the bloodstream
Transthyretin (thyroid-binding prealbumin – TBPA) and albumin
o Bind most of the remaining thyroid hormones
About 0.3 percent of T3 and 0.03 percent of T4 are unbound
18-4 The Thyroid Gland
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Thyroid-Stimulating Hormone (TSH)
o Absence causes thyroid follicles to become inactive
 Neither synthesis nor secretion occurs
o Binds to membrane receptors
o Activates key enzymes in thyroid hormone production
18-4 The Thyroid Gland
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Functions of Thyroid Hormones
o Thyroid Hormones
 Enter target cells by transport system
 Affect most cells in body
 Bind to receptors in:
1. Cytoplasm
2. Surfaces of mitochondria
3. Nucleus
 In children, essential to normal development of:
o Skeletal, muscular, and nervous systems
18-4 The Thyroid Gland
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Calorigenic Effect
o Cell consumes more energy resulting in increased heat generation
o Is responsible for strong, immediate, and short-lived increase in rate of
cellular metabolism
18-4 The Thyroid Gland
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Effects of Thyroid Hormones on Peripheral Tissues
1. Elevates rates of oxygen consumption and energy consumption; in
children, may cause a rise in body temperature
2. Increases heart rate and force of contraction; generally results in a rise in
blood pressure
3. Increases sensitivity to sympathetic stimulation
4. Maintains normal sensitivity of respiratory centers to changes in oxygen
and carbon dioxide concentrations
5. Stimulates red blood cell formation and thus enhances oxygen delivery
6. Stimulates activity in other endocrine tissues
7. Accelerates turnover of minerals in bone
18-4 The Thyroid Gland
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The C Cells of the Thyroid Gland and Calcitonin
o C (clear) cells also called parafollicular cells
o Produce calcitonin (CT)
 Helps regulate concentrations of Ca2+ in body fluids
1. Inhibits osteoclasts, which slows the rate of Ca2+ release from bone
2. Stimulates Ca2+ excretion by the kidneys
An Introduction to Blood and the Cardiovascular System

Blood
o Transports materials to and from cells
 Oxygen and carbon dioxide
 Nutrients
 Hormones
 Immune system components
 Waste products
19-1 Physical Characteristics of Blood
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Important Functions of Blood
o Transportation of dissolved substances
o Regulation of pH and ions
o Restriction of fluid losses at injury sites
o Defense against toxins and pathogens
o Stabilization of body temperature
19-1 Physical Characteristics of Blood
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Whole Blood
o Plasma
 Fluid consisting of:
o Water
o Dissolved plasma proteins
o Other solutes
o Formed elements
 All cells and solids
19-1 Physical Characteristics of Blood
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Three Types of Formed Elements
1. Red blood cells (RBCs) or erythrocytes
 Transport oxygen
2. White blood cells (WBCs) or leukocytes
 Part of the immune system
3. Platelets
 Cell fragments involved in clotting
19-1 Physical Characteristics of Blood
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Hemopoiesis
o Process of producing formed elements
o By myeloid and lymphoid stem cells
Fractionation
o Process of separating whole blood for clinical analysis
 Into plasma and formed elements
19-1 Physical Characteristics of Blood
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Three General Characteristics of Blood
1. 38C (100.4F) is normal temperature
2. High viscosity
3. Slightly alkaline pH (7.35–7.45)
19-1 Physical Characteristics of Blood
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Characteristics of Blood
o Blood volume (liters)  7 percent of body weight (kilograms)
 Adult male: 5–6 liters
 Adult female: 4–5 liters
19-2 Plasma
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The Composition of Plasma
o Makes up 50–60 percent of blood volume
o More than 90 percent of plasma is water
o Extracellular fluids
 Interstitial fluid (IF) and plasma
 Materials plasma and IF exchange across capillary walls
o Water
o Ions
o Small solutes
19-2 Plasma
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Plasma Proteins
o Albumins (60 percent)
o Globulins (35 percent)
o Fibrinogen (4 percent)
19-2 Plasma
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Albumins (60 percent)
o Transport substances such as fatty acids, thyroid hormones, and steroid
hormones
Globulins (35 percent)
o Antibodies, also called immunoglobulins
o Transport globulins (small molecules): hormone-binding proteins,
metalloproteins, apolipoproteins (lipoproteins), and steroid-binding
proteins
Fibrinogen (4 percent)
o Molecules that form clots and produce long, insoluble strands of fibrin
19-2 Plasma
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Serum
o Liquid part of a blood sample
 In which dissolved fibrinogen converts to solid fibrin
19-2 Plasma
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Other Plasma Proteins
o 1 percent of plasma
 Changing quantities of specialized plasma proteins
 Peptide hormones normally present in circulating blood
o Insulin, prolactin (PRL), and the glycoproteins thyroid-stimulating
hormone (TSH), follicle-stimulating hormone (FSH), and luteinizing
hormone (LH)
19-2 Plasma
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Origins of Plasma Proteins
o More than 90 percent made in liver
o Antibodies made by plasma cells
o Peptide hormones made by endocrine organs
19-3 Red Blood Cells
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Red blood cells (RBCs)
o Make up 99.9 percent of blood’s formed elements
Hemoglobin
o The red pigment that gives whole blood its color
o Binds and transports oxygen and carbon dioxide
19-3 Red Blood Cells
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Abundance of RBCs
o Red blood cell count – the number of RBCs in 1 microliter of whole blood
 Male: 4.5–6.3 million
 Female: 4.2–5.5 million
19-3 Red Blood Cells

Abundance of RBCs
o Hematocrit – (packed cell volume, PCV) percentage of RBCs in
centrifuged whole blood
 Male: 40–54
 Female: 37–47
19-3 Red Blood Cells
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Structure of RBCs
o Small and highly specialized discs
o Thin in middle and thicker at edge
19-3 Red Blood Cells
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Three Important Effects of RBC Shape on Function
1. High surface-to-volume ratio
 Quickly absorbs and releases oxygen
2. Discs form stacks called rouleaux
 Smooth the flow through narrow blood vessels
3. Discs bend and flex entering small capillaries
 7.8-µm RBC passes through 4-µm capillary
19-3 Red Blood Cells
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Life Span of RBCs
o Lack nuclei, mitochondria, and ribosomes
 Means no repair and anaerobic metabolism
 Live about 120 days
19-3 Red Blood Cells
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Hemoglobin (Hb)
o Protein molecule that transports respiratory gases
o Normal hemoglobin (adult male)
 14–18 g/dL whole blood
o Normal hemoglobin (adult female)
 12–16 g/dL whole blood
19-3 Red Blood Cells
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Hemoglobin Structure
o Complex quaternary structure
o Four globular protein subunits
 Each with one molecule of heme
 Each heme contains one iron ion
19-3 Red Blood Cells
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Hemoglobin Structure
o Iron ions
 Associate easily with oxygen (oxyhemoglobin, HbO2)
 Dissociate easily from oxygen (deoxyhemoglobin)
19-3 Red Blood Cells
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Fetal Hemoglobin
o Strong form of hemoglobin found in embryos
o Takes oxygen from mother’s hemoglobin
19-3 Red Blood Cells
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Hemoglobin Function
o Carries oxygen
o With low oxygen (peripheral capillaries):
 Hemoglobin releases oxygen
 Binds carbon dioxide and carries it to lungs
o Forms carbaminohemoglobin
19-3 Red Blood Cells
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RBC Formation and Turnover
o 1 percent of circulating RBCs wear out per day
 About 3 million new RBCs per second
Hemoglobin Conversion and Recycling
o Macrophages of liver, spleen, and bone marrow
 Monitor RBCs

Engulf RBCs before membranes rupture (hemolyze)
19-3 Red Blood Cells
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Hemoglobin Conversion and Recycling
o Phagocytes break hemoglobin into components
 Globular proteins to amino acids
 Heme to biliverdin
 Iron
19-3 Red Blood Cells
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Hemoglobin Conversion and Recycling
o Hemoglobinuria
 Hemoglobin breakdown products in urine due to excess hemolysis in
bloodstream
o Hematuria
 Whole red blood cells in urine due to kidney or tissue damage
19-3 Red Blood Cells
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Breakdown of Biliverdin
o Biliverdin (green) is converted to bilirubin (yellow)
 Bilirubin
o Is excreted by liver (bile)
o Jaundice is caused by bilirubin buildup
o Converted by intestinal bacteria to urobilins and stercobilins
19-3 Red Blood Cells
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Iron Recycling
o Iron removed from heme leaving biliverdin
o To transport proteins (transferrin)
o To storage proteins (ferritin and hemosiderin)
19-3 Red Blood Cells
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RBC Production
o Erythropoiesis
 Occurs only in myeloid tissue (red bone marrow) in adults
 Stem cells mature to become RBCs
19-3 Red Blood Cells
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Hemocytoblasts
o Stem cells in myeloid tissue divide to produce:
1. Myeloid stem cells become RBCs, some WBCs
2. Lymphoid stem cells become lymphocytes
19-3 Red Blood Cells
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Stages of RBC Maturation
o Myeloid stem cell
o Proerythroblast
o Erythroblasts
o Reticulocyte
o Mature RBC
19-3 Red Blood Cells
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Regulation of Erythropoiesis
o Building red blood cells requires:
 Amino acids
 Iron
 Vitamins B12, B6, and folic acid
o Pernicious anemia
Low RBC production
Due to unavailability of vitamin B12
19-3 Red Blood Cells
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Stimulating Hormones
o Erythropoietin (EPO)
 Also called erythropoiesis-stimulating hormone
 Secreted when oxygen in peripheral tissues is low (hypoxia)
 Due to disease or high altitude
19-4 Blood Typing
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Surface Antigens
o Are cell surface proteins that identify cells to immune system
o Normal cells are ignored and foreign cells attacked
Blood Types
o Are genetically determined
o By presence or absence of RBC surface antigens A, B, Rh (or D)
19-4 Blood Typing
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Four Basic Blood Types
1. A (surface antigen A)
2. B (surface antigen B)
3. AB (antigens A and B)
4. O (neither A nor B)
19-4 Blood Typing
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Agglutinogens
o Antigens on surface of RBCs
o Screened by immune system
o Plasma antibodies attack and agglutinate (clump) foreign antigens
19-4 Blood Typing
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Blood Plasma Antibodies
o Type A
 Type B antibodies
o Type B
 Type A antibodies
o Type O
 Both A and B antibodies
o Type AB
 Neither A nor B antibodies
19-4 Blood Typing
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The Rh Factor
o Also called D antigen
o Either Rh positive (Rh+) or Rh negative (Rh–)
 Only sensitized Rh– blood has anti-Rh antibodies
19-4 Blood Typing
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Cross-Reactions in Transfusions
o Also called transfusion reaction
o Plasma antibody meets its specific surface antigen
o Blood will agglutinate and hemolyze
o Occur if donor and recipient blood types not compatible
19-4 Blood Typing
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Testing for Transfusion Compatibility
o Performed on donor and recipient blood for compatibility
o Without cross-match, type O– is universal donor