Hormones and Blood Hormones and Blood SugarSugar

Key PlayersKey Players

In regards to maintaining blood sugar In regards to maintaining blood sugar levels…levels…

The PancreasThe Pancreas The Liver The Liver

Player #1Player #1

The pancreasThe pancreas Contains two types of cells…Contains two types of cells… Digestive EnzymesDigestive Enzymes Focus on Focus on hormone producing cellshormone producing cells

Islets of LangerhansIslets of Langerhans Located where ??Located where ??

Islets of LangerhansIslets of Langerhans

Islets of LangerhansIslets of Langerhans

Contain Alpha and Beta CellsContain Alpha and Beta Cells Alpha Cells: Secrete GlucagonAlpha Cells: Secrete Glucagon Beta Cells: Secrete InsulinBeta Cells: Secrete Insulin

Player #2Player #2

The LiverThe Liver Stores Glucose in the form of Stores Glucose in the form of

glycogenglycogen

Before We Look At Before We Look At Mechanisms…Mechanisms…

Must understand:Must understand: Body has created Positive and Body has created Positive and

Negative feedback systemsNegative feedback systems

Positive FeedbackPositive Feedback

Designed to accelerate or enhance a Designed to accelerate or enhance a response that has already startedresponse that has already started

Pushes systems outside of their Pushes systems outside of their normal rangenormal range

ExampleExample

During Childbirth:During Childbirth: Pressure receptors encourage the release Pressure receptors encourage the release

of Oxytocin in the Pituitary Glandof Oxytocin in the Pituitary Gland Oxytocin causes contractions Oxytocin causes contractions Pressure increases on the pressure Pressure increases on the pressure

sensorssensors After the child is born, the pressure After the child is born, the pressure

receptors are no longer stimulated and receptors are no longer stimulated and Oxytocin production ceasesOxytocin production ceases

Pressure Sensors cause the release of oxytocin

Oxytocin causes contractions to intensify

More intense contractions cause more pressure

Negative FeedbackNegative Feedback

Designed to maintain the body Designed to maintain the body systems within appropriate systems within appropriate parametersparameters

Mechanisms are activated to restore Mechanisms are activated to restore conditions to their normal stateconditions to their normal state

Keeps delicate systems working Keeps delicate systems working ideally and preserves body functionideally and preserves body function

ExampleExample

Calcium LevelsCalcium Levels If calcium levels in the blood are too low the If calcium levels in the blood are too low the

parathyroid releases parathyroid hormoneparathyroid releases parathyroid hormone Parathyroid hormone causes the bones to Parathyroid hormone causes the bones to

release calciumrelease calcium Parathyroid hormone also causes intestines Parathyroid hormone also causes intestines

to absorb more calciumto absorb more calcium Blood calcium levels then return to normalBlood calcium levels then return to normal

Example cont’dExample cont’d

Calcium Levels cont’dCalcium Levels cont’d If your calcium levels in your blood are If your calcium levels in your blood are

too hightoo high The thyroid produces calcitoninThe thyroid produces calcitonin Calcitonin increases the uptake of Calcitonin increases the uptake of

calcium to the bonescalcium to the bones Calcium levels return to normalCalcium levels return to normal

ThereforeTherefore

In the body we see more Negative In the body we see more Negative Feedback Systems…Feedback Systems…

As part of homeostasisAs part of homeostasis And as you can see it is very And as you can see it is very

Structured, precise and complex.Structured, precise and complex.

Back to Blood SugarBack to Blood Sugar

Glucose Regulation

You DecideYou Decide

Positive or Negative Feedback ??Positive or Negative Feedback ?? Discuss and Explain Your ReasoningDiscuss and Explain Your Reasoning

DiabetesDiabetes

Caused by insufficient production or Caused by insufficient production or use of insulin.use of insulin.

If untreated causes: blindness, If untreated causes: blindness, kidney failure and nerve damage.kidney failure and nerve damage.

InsulinInsulin

Without adequate levels Without adequate levels Blood sugar levels rises quickly Blood sugar levels rises quickly

following mealsfollowing meals Kidneys are unable to reabsorb all Kidneys are unable to reabsorb all

the blood glucose being filteredthe blood glucose being filtered

What does insulin do…What does insulin do…

Required for cells of the body to Required for cells of the body to become permeable to glucosebecome permeable to glucose

Therefore if insulin isn’t present Therefore if insulin isn’t present glucose cannot enter cells and they glucose cannot enter cells and they become “starved” become “starved”

Type 1 & Type 2 DiabetesType 1 & Type 2 Diabetes

Type 1: Juvenile on-setType 1: Juvenile on-set Occurs when the pancreas cannot produce Occurs when the pancreas cannot produce

insulin because of the degeneration of beta insulin because of the degeneration of beta cells in the islets of Langerhanscells in the islets of Langerhans

Type 2:Adult on-setType 2:Adult on-set Decreased insulin production or ineffective Decreased insulin production or ineffective

useuse Can be controlled by diet, exercise or oral Can be controlled by diet, exercise or oral

drugs (sulfonamides)drugs (sulfonamides)

Adrenal Glands – Regulating Adrenal Glands – Regulating BSLBSL

Already Know – Located on top of the Already Know – Located on top of the kidneyskidneys

Release the hormones epinephrine Release the hormones epinephrine and norepinephrineand norepinephrine

How do these affect Blood Sugar How do these affect Blood Sugar Levels ?Levels ?

Nervous system senses a stressful situationNervous system senses a stressful situation Short-term:Short-term: Adrenal medulla releases epinephrine and Adrenal medulla releases epinephrine and

norepinephrine into the bloodnorepinephrine into the blood This causes a rise in blood sugar levelsThis causes a rise in blood sugar levels Glucagon converted to glucoseGlucagon converted to glucose

Why do you think this is important ??Why do you think this is important ??

Long-term:Long-term: Adrenal cortex releases Adrenal cortex releases

glucocorticoids glucocorticoids and mineralocorticoidsand mineralocorticoids Glucocorticoids help the body meet Glucocorticoids help the body meet

the demands of stress. the demands of stress. Cortisol – increases amino acids in Cortisol – increases amino acids in

bloodblood

QuestionsQuestions

P. 383 # 2,3,4,5P. 383 # 2,3,4,5

Q. 2 – How Does Insulin Q. 2 – How Does Insulin regulate blood sugar levels ?regulate blood sugar levels ?

Insulin decreases blood sugar levels. When blood sugars are high, insulin is released. Insulin increases glucose utilization by making cells more permeable to glucose, and blood sugar levels are returned to a normal range.

Q.3 - Q.3 - How does glucagon regulate blood sugar levels?

Glucagon increases blood sugar levels. When blood sugar levels are low, glucagon is released and liver glycogen is converted into glucose. Blood sugar levels rise as glucose leaves the liver.

Q.4 - Q.4 - Using a flow chart, show a homeostatic adjustment for a person who has consumeda significant amount of carbohydrates in the

past hour.

Q.5 - Q.5 - What advantage is provided by increasing blood sugar above normal levels

in timesof stress?

This provides more glucose for cells. Glucose can be converted to adenosine triphosphate (ATP), the cellular fuel. This ensures that greater energy will be available to the tissues of the body.