found at: the base of the throat consists of: two lobes and a connecting isthmus produces two...
TRANSCRIPT
Found at: the base of the throat
Consists of:two lobes and a connecting isthmus
Produces two hormones1. Thyroid hormone2. Calcitonin
Thyroid Gland1. Thyroid hormone
Major metabolic hormoneComposed of two active iodine-containing hormonesThyroxine (T4)—secreted by thyroid follicles
Triiodothyronine (T3)—conversion of T4 at target tissues
Thyroid Gland
Thyroid Hormone DisordersGoiters
Thyroid gland enlarges In U.S., rarely see goiters due to lack of iodine because we use “iodized” salt
Goiters
Thyroid Hormone DisordersCretinism
Caused by hyposecretion of thyroxineLack of iodineCongenital lack of thyroid gland
Results in stunted physical and mental growth during childhood
Cretinism
Thyroid Hormone DisordersMyxedemaCaused by hypothyroidism in adults
Results in physical and mental slugishness
Myxedema
Thyroid Hormone DisordersGrave’s Disease
Caused by hyperthyroidismResults in:
increased metabolismheat intolerancerapid heartbeatweight lossexophthalmos
Exophthalmos
Thyroid Gland2. Calcitonin
Decreases blood calcium levels by causing its deposition on bone
Antagonistic to parathyroid hormone
Produced by parafollicular cells
Parathyroid GlandTiny masses (4) on the posterior of the
thyroid
Parathyroid GlandSecrete parathyroid hormone (PTH)
Raise calcium levels in the blood1. Stimulate osteoclasts to remove
calcium from bone2. Stimulate the kidneys and intestine
to absorb more calcium
Calcium homeostasis of blood9–11 mg/100 ml
RisingbloodCa2+
levels
Imbalance
Imbalance
Calcium homeostasis of blood9–11 mg/100 ml
RisingbloodCa2+
levels
Thyroidgland
Imbalance
Imbalance
Calcium homeostasis of blood9–11 mg/100 ml
RisingbloodCa2+
levels
Thyroid glandreleasescalcitonin
Calcitonin
Thyroidgland
Imbalance
Imbalance
Calcium homeostasis of blood9–11 mg/100 ml
RisingbloodCa2+
levels
Thyroid glandreleasescalcitonin
Calcitonin Calcitoninstimulatescalcium saltdepositin bone
Thyroidgland
Imbalance
Imbalance
Calcium homeostasis of blood9–11 mg/100 ml
RisingbloodCa2+
levels
Thyroid glandreleasescalcitonin
Calcitonin Calcitoninstimulatescalcium saltdepositin bone
Thyroidgland
Calcium homeostasis of blood9–11 mg/100 ml
FallingbloodCa2+
levels
Imbalance
Imbalance
Calcium homeostasis of blood9–11 mg/100 ml
Thyroidgland
Parathyroidglands
FallingbloodCa2+
levels
Imbalance
Imbalance
Calcium homeostasis of blood9–11 mg/100 ml
PTHParathyroidglands releaseparathyroidhormone (PTH)
Thyroidgland
Parathyroidglands
FallingbloodCa2+
levels
Imbalance
Imbalance
Calcium homeostasis of blood9–11 mg/100 ml
Osteoclastsdegrade bonematrix and releaseCa2+ into blood
PTHParathyroidglands releaseparathyroidhormone (PTH)
Thyroidgland
Parathyroidglands
FallingbloodCa2+
levels
Imbalance
Imbalance
Calcium homeostasis of blood9–11 mg/100 ml
Osteoclastsdegrade bonematrix and releaseCa2+ into blood
PTHParathyroidglands releaseparathyroidhormone (PTH)
Thyroidgland
Parathyroidglands
Calcium Homeostasis
Adrenal GlandsSit on top of the kidneysTwo regions
1. Adrenal cortex—outer glandular region has three layersA. Mineralocorticoids secreting areaB. Glucocorticoids secreting areaC. Sex hormones secreting area
2. Adrenal medulla—inner neural tissue region. When stimulated, it releases EPINEPHRINE and NOREPINEPHRINE
Adrenal Cortex
Adrenal CortexMineralocorticoid layer secretes ALDOSTERONE
Aldosterone is important for sodium (Na+) and potassium (K+) balance; works on kidneys
Glucocorticoid layer secretes CORTISOL and CORTISONEHelp resist long-term stressorsReleased in response to increased blood levels of
ACTHSex hormone layer secretes small amount of
ANDROGENS and ESTROGENS
Short term Stress
Hypothalamus
Short term Stress
Hypothalamus
Nerve impulses
Spinal cord
Short term Stress
Hypothalamus
Nerve impulses
Spinal cord
Adrenalmedulla
Preganglionicsympatheticfibers
Short term Stress
Hypothalamus
Nerve impulses
Short-termstress response
Spinal cord
Adrenalmedulla
Preganglionicsympatheticfibers
Catecholamines(epinephrine andnorepinephrine)
More prolongedStress
Hypothalamus
More prolongedStress
Hypothalamus
Adrenalcortex
Releasing hormone
Corticotropic cells ofanterior pituitary
ACTH
More prolongedStress
Hypothalamus
Adrenalcortex
Releasing hormone
Corticotropic cells ofanterior pituitary
ACTH
Mineralocorticoids Glucocorticoids
Long-term stress response
Adrenal cortex disordersAddison’s disease
Results from hyposecretion of all adrenal cortex hormones
Bronze skin tone, muscles are weak, burnout, susceptibility to infection
Adrenal cortex disorders
Adrenal cortex disordersCushing’s syndrome
Results from a tumor in the middle cortical area of the adrenal cortex
Characterized by:“Moon face” “Buffalo hump” on the upper backHigh blood pressureIncreased blood sugarDepression
Cushing’s Syndrome
PancreasThe pancreas is a mixed gland and has both endocrine and exocrine functions
Pancreatic Islets: 2 Hormones1. Insulin (beta cells): allows
glucose to cross plasma membranes into cells
2. Glucagon (alpha cells): allows glucose stored in cells to be released into the blood
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Stimulus:rising bloodglucose levels(e.g., aftereating fourjelly doughnuts)
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Imbalance
Imbalance
Elevatedblood sugarlevels
Stimulus:rising bloodglucose levels(e.g., aftereating fourjelly doughnuts)
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Imbalance
Imbalance
Insulin-secretingcells of the pancreasactivated; releaseinsulin into theblood
Elevatedblood sugarlevels
Stimulus:rising bloodglucose levels(e.g., aftereating fourjelly doughnuts)
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Imbalance
Imbalance
Insulin-secretingcells of the pancreasactivated; releaseinsulin into theblood
Elevatedblood sugarlevels
Stimulus:rising bloodglucose levels(e.g., aftereating fourjelly doughnuts)
Uptake of glucosefrom blood is en-hanced in mostbody cells
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Imbalance
Imbalance
Insulin-secretingcells of the pancreasactivated; releaseinsulin into theblood
Elevatedblood sugarlevels
Stimulus:rising bloodglucose levels(e.g., aftereating fourjelly doughnuts)
Uptake of glucosefrom blood is en-hanced in mostbody cells
Liver takes upglucose and storesit as glycogen
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Imbalance
Imbalance
Insulin-secretingcells of the pancreasactivated; releaseinsulin into theblood
Elevatedblood sugarlevels
Stimulus:rising bloodglucose levels(e.g., aftereating fourjelly doughnuts)
Blood glucoselevels declineto set point;stimulus forinsulin releasediminishes
Uptake of glucosefrom blood is en-hanced in mostbody cells
Liver takes upglucose and storesit as glycogen
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Stimulus:declining bloodglucose levels(e.g., afterskipping a meal)
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Imbalance
Imbalance
Stimulus:declining bloodglucose levels(e.g., afterskipping a meal)
Low bloodsugar levels
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Imbalance
Imbalance
Stimulus:declining bloodglucose levels(e.g., afterskipping a meal)
Low bloodsugar levels
Glucagon-releasingcells of pancreasactivated;release glucagoninto blood; targetis the liver
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Imbalance
Imbalance
Stimulus:declining bloodglucose levels(e.g., afterskipping a meal)
Low bloodsugar levels
Glucagon-releasingcells of pancreasactivated;release glucagoninto blood; targetis the liverLiver breaks down
glycogen stores andreleases glucose tothe blood
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Imbalance
Imbalance
Rising bloodglucose levelsreturn blood sugarto homeostatic setpoint; stimulus forglucagon releasediminishes
Stimulus:declining bloodglucose levels(e.g., afterskipping a meal)
Low bloodsugar levels
Glucagon-releasingcells of pancreasactivated;release glucagoninto blood; targetis the liverLiver breaks down
glycogen stores andreleases glucose tothe blood
Homeostasis: Normal blood glucoselevels (90 mg/100ml)
Pineal GlandFound on the third ventricle of the
brain
Pineal GlandCalled the “third eye” because it
receives visual information from the retina regarding light and dark
Secretes melatoninHelps establish the body’s wake and sleep cycles