REGULATION THE ENDOCRINE SYSTEM

REGULATION REGULATION THE ENDOCRINE SYSTEMTHE ENDOCRINE SYSTEM

Body System which Body System which regulates:regulates:

overall metabolismoverall metabolism homeostasishomeostasis growth growth reproductionreproduction

ENDOCRINE GLANDSENDOCRINE GLANDS

Ductless organs Ductless organs that secrete that secrete hormones directly hormones directly into the into the bloodstream to be bloodstream to be transported to transported to other parts of the other parts of the bodybody

HORMONESHORMONES

Chemical messengers Chemical messengers that cause a change that cause a change in target tissues in target tissues activity activity

Examples:Examples:

Insulin (protein-type)Insulin (protein-type)

Testosterone (steroid)Testosterone (steroid)

HormonesHormones

Hyposecretion- a Hyposecretion- a deficiency of a deficiency of a hormonehormone

Hypersecretion- an Hypersecretion- an excess of a excess of a hormonehormone

Target TissuesTarget Tissues

Tissue that is Tissue that is affected by a affected by a particular hormone particular hormone

Different than the Different than the secreting glandsecreting gland

DYNAMIC EQUILIBRIUMDYNAMIC EQUILIBRIUM

Steady StateSteady State Constant small Constant small

corrections that corrections that normally occur to normally occur to keep an organism’s keep an organism’s internal internal environment within environment within limits needed for limits needed for survival (stable)survival (stable)

HOMEOSTASISHOMEOSTASIS

Feedback MechanismFeedback Mechanism

Cycle in which output of a system Cycle in which output of a system “feeds back”“feeds back”

Either modifies or reinforces the Either modifies or reinforces the action of the systemaction of the system

Feedback responses can be simple or Feedback responses can be simple or complexcomplex

Positive FeedbackPositive Feedback

Change in Change in environment environment prompts a responseprompts a response

Response leads to Response leads to greater change and greater change and greater responsegreater response

ReinforcesReinforces Labor and childbirth Labor and childbirth

is an exampleis an example

Negative FeedbackNegative Feedback

Change prompts Change prompts signal which leads signal which leads to a decrease or to a decrease or stop of original stop of original response- opposesresponse- opposes

Most commonMost common Keeps levels Keeps levels

constantconstant Maintains Maintains

HomeostasisHomeostasis

FEEDBACKFEEDBACK

Negative FeedbackNegative Feedback

Examples:Examples: Regulating human body temperatureRegulating human body temperature

Negative FeedbackNegative Feedback

Regulates blood glucose levelsRegulates blood glucose levels

Sugar level highSugar level high

neg feedbackneg feedback

PancreasPancreas low blood low blood sugarsugar

Secretes insulin Secretes insulin product product decreasesdecreases

insulininsulin

Blood sugar dropsBlood sugar drops

Pituitary GlandPituitary Gland Is sometimes called “The Master Is sometimes called “The Master

Gland” because it controls the other Gland” because it controls the other endocrine glandsendocrine glands

It is located at the base of the brainIt is located at the base of the brain

Pituitary HormonesPituitary Hormones

Thyroid Stimulating Hormone (TSH)Thyroid Stimulating Hormone (TSH) Causes the thyroid gland to release it’s Causes the thyroid gland to release it’s

hormone (thyroxine)hormone (thyroxine)

Pituitary HormonesPituitary Hormones

Follicle Stimulating Follicle Stimulating Hormone (FSH)Hormone (FSH) Causes human egg Causes human egg

cells to develop in cells to develop in the ovaries and the ovaries and influences other influences other reproductive reproductive hormoneshormones

Pituitary HormonesPituitary Hormones

Growth Hormone (GH)Growth Hormone (GH) Causes bones to grow normally during Causes bones to grow normally during

childhood childhood

Pituitary HormonesPituitary Hormones

Adrenocorticotropic Hormone (ACTH)Adrenocorticotropic Hormone (ACTH) Stimulates the production and release of Stimulates the production and release of

hormones from the adrenal glandshormones from the adrenal glands

Thyroid GlandThyroid Gland

The thyroid gland is H shaped and is The thyroid gland is H shaped and is located in the neck around the located in the neck around the tracheatrachea It produces thyroxine that regulates the It produces thyroxine that regulates the

rate of body metabolism and is rate of body metabolism and is necessary for normal mental and necessary for normal mental and physical developmentphysical development

Contains IodineContains Iodine

Parathyroid glandsParathyroid glands

The parathyroid glands are located The parathyroid glands are located within the thyroid glandwithin the thyroid gland They produce the hormone They produce the hormone

parathormone which controls the levels parathormone which controls the levels of calcium and phosphorus of calcium and phosphorus

Adrenal glandsAdrenal glands The adrenal glands The adrenal glands

are located at the top are located at the top of the kidneys and of the kidneys and produce the hormones produce the hormones adrenaline and cortisoladrenaline and cortisol Cortisol regulates sugar Cortisol regulates sugar

metabolism, water metabolism, water balance and helps to balance and helps to maintain blood pressuremaintain blood pressure

Adrenaline increases Adrenaline increases sugar levels in the sugar levels in the blood, increases heart blood, increases heart and breathing rates to and breathing rates to get body ready for get body ready for “fight or flight”“fight or flight”

PancreasPancreas The pancreas has cells called the islets of The pancreas has cells called the islets of

langerhanslangerhans These cells produce the hormones insulin and These cells produce the hormones insulin and

glucagonglucagon

Insulin lowers blood glucose levels by Insulin lowers blood glucose levels by increasing the movement of glucose into the increasing the movement of glucose into the body cellsbody cells

Within the cells of the liver insulin promotes Within the cells of the liver insulin promotes the change of glucose to glycogen (a the change of glucose to glycogen (a polysaccharide)polysaccharide)

PancreasPancreas Glucagon raises blood glucose levels Glucagon raises blood glucose levels

by promoting the change of glycogen by promoting the change of glycogen in the liver back to glucosein the liver back to glucose

Gonads – Sex GlandsGonads – Sex Glands

The testes are located The testes are located in the male scrotum in the male scrotum and produce the and produce the hormone testosteronehormone testosterone Testosterone promotes Testosterone promotes

the development of the development of secondary sex secondary sex characteristics in males characteristics in males (deep voice, facial and (deep voice, facial and body hair, and the male body hair, and the male body form) body form)

Gonads – Sex GlandsGonads – Sex Glands

The ovaries are located The ovaries are located in the lower abdomen of in the lower abdomen of females and produce the females and produce the hormones estrogen and hormones estrogen and progesteroneprogesterone

Estrogen stimulates the development of Estrogen stimulates the development of the female reproductive system and the the female reproductive system and the female secondary sex characteristics female secondary sex characteristics (development of breasts, broadening of (development of breasts, broadening of hips and with progesterone, regulation hips and with progesterone, regulation of the menstrual cycle)of the menstrual cycle)

Malfunctions of the Endocrine Malfunctions of the Endocrine SystemSystem

Thyroid- HyperthyroidismThyroid- Hyperthyroidism Hypersecretion of thyroxine = increased Hypersecretion of thyroxine = increased

metabolism, nervousness, irritability, metabolism, nervousness, irritability, sleeplessness and weight losssleeplessness and weight loss

May produce a goiter, an enlargement of May produce a goiter, an enlargement of the thyroid gland (which may be caused the thyroid gland (which may be caused by lack of iodine in the diet)by lack of iodine in the diet)

Thyroid- Thyroid- HypothyroidismHypothyroidism Hyposecretion of Hyposecretion of

thyroxine in infancy thyroxine in infancy may cause cretinism may cause cretinism (child will be mentally (child will be mentally retarded and a dwarf)retarded and a dwarf)

In adults sluggishness In adults sluggishness and weight gain due and weight gain due to decrease in to decrease in metabolismmetabolism

Pituitary Pituitary Hypersecretion Hypersecretion

of GH in of GH in children leads children leads to gigantism to gigantism where the where the individual is individual is abnormally tall abnormally tall but in but in proportionproportion

In adults In adults acromegaly – acromegaly – large hands, large hands, feet and facial feet and facial featuresfeatures

Pituitary Pituitary Hyposecretion of GH leads to dwarfism Hyposecretion of GH leads to dwarfism

where the individual is small but where the individual is small but normally proportionednormally proportioned

PancreasPancreas Hypersecretion of insulin can lead to Hypersecretion of insulin can lead to

diabetic shock because blood glucose diabetic shock because blood glucose levels fall dangerously lowlevels fall dangerously low

Convulsions, unconsciousness and death Convulsions, unconsciousness and death may resultmay result

PancreasPancreas Hyposecretion of insulin causes diabetesHyposecretion of insulin causes diabetes The glucose does not move into the cells The glucose does not move into the cells

and the blood glucose level risesand the blood glucose level rises High blood glucose levels can damage High blood glucose levels can damage

organs and tissuesorgans and tissues Insulin injections are given to control the Insulin injections are given to control the

blood glucose levelsblood glucose levels