Blood sugar regulation
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Blood Sugar Regulation. Pancreas. Pancreas. Pancreas. Two cell types to produce: digestive enzymes – exocrine glands (acini) hormones – islets of Langerhans. 1 – 2% of pancreas are the islets of Langerhans. Islets of Langerhans. Two hormones are produced: insulin – beta ( β ) cells

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Blood Sugar Regulation

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Blood sugar regulation

Blood Sugar Regulation


Pancreas

Pancreas


Pancreas1

Pancreas


Pancreas2

Pancreas

Two cell types to produce:

  • digestive enzymes – exocrine glands (acini)

  • hormones – islets of Langerhans

1 – 2% of pancreas are the islets of Langerhans


Islets of langerhans

Islets of Langerhans

Two hormones are produced:

  • insulin – beta (β) cells

  • glucagon – alpha (α) cells

blue = cell nuclei

green = insulin

red = glucagon


Hormone structure

Hormone Structure

  • insulin

    • peptide hormone

  • glucagon

    • peptide hormone

  • Insulin and glucagon are referred to as antagonistic hormones.


Glycogen

Glycogen

  • A glucose polymer made up of many glucose subunits

  • “Storage form of glucose”

  • Stored within liver and muscle


Action of insulin

Body cells

take up more

glucose.

Insulin

Beta cells of

pancreas are stimulated

to release insulin

into the blood.

Liver takes

up glucose

and stores it

as glycogen.

STIMULUS:

Rising blood glucose

level (for instance, after

eating a carbohydrate-

rich meal)

Blood glucose level

declines to set point;

stimulus for insulin

release diminishes.

Homeostasis:

Blood glucose level

(about 90 mg/100 mL)

Blood glucose level

rises to set point;

stimulus for glucagon

release diminishes.

STIMULUS:

Dropping blood glucose

level (for instance, after

skipping a meal)

Alpha cells of pancreas

are stimulated to release

glucagon into the blood.

Liver breaks

down glycogen

and releases

glucose into

blood.

Glucagon

Figure 45.12

Action of Insulin

  • c


Example of insulin s effect on body cells muscle cell

Example of Insulin’s Effect on Body Cells - Muscle Cell

Glucose

OUTSIDE CELL

Insulin

Insulin Receptors

Signal Transduction Pathway

Exocytosis

INSIDE CELL

GLUT 4 Transporters (proteins that transport glucose across plasma membrane)

GLUT 4 Protein Vesicles


Blood sugar regulation

When is insulin released? after eating

hyperglycemia

beta cells

decreased blood sugar

cellular signals for insulin release

increased glucose uptake

glycogen production in liver


Action of glucagon

Body cells

take up more

glucose.

Insulin

Beta cells of

pancreas are stimulated

to release insulin

into the blood.

Liver takes

up glucose

and stores it

as glycogen.

STIMULUS:

Rising blood glucose

level (for instance, after

eating a carbohydrate-

rich meal)

Blood glucose level

declines to set point;

stimulus for insulin

release diminishes.

Homeostasis:

Blood glucose level

(about 90 mg/100 mL)

Blood glucose level

rises to set point;

stimulus for glucagon

release diminishes.

STIMULUS:

Dropping blood glucose

level (for instance, after

skipping a meal)

Alpha cells of pancreas

are stimulated to release

glucagon into the blood.

Liver breaks

down glycogen

and releases

glucose into

blood.

Glucagon

Action of Glucagon


Blood sugar regulation

What does glucagon do? breaks down glycogen

hypoglycemia

alpha cells

increased blood sugar

cellular signals for glucagon release

glucose release from liver

glucose production in liver


Diabetes mellitus type i

Diabetes Mellitus – Type I

  • also known as juvenile diabetes or insulin-dependent diabetes

    Cause

    • immune system attacking insulin-producing beta cells

    • no insulin production

      Symptoms

    • increased thirst, hunger and urination

      Treatment

    • daily dosage of insulin


Diabetes mellitus type ii

Diabetes Mellitus – Type II

  • also known as adult-onset diabetes or non-insulin-dependent diabetes

    Cause

  • Poor diet, lack of exercise

    • Excess glucose in the blood for a long period of time causes the pancreas to become overworked and tired

  • Beta cells produce some, but not enough insulin (deficiency)

  • A reduction in the number of functional insulin receptors

    • reduced responsiveness of cells to insulin = insulin resistant

Symptoms

  • increased thirst, hunger and urination

  • fatigue / lethargy


Type ii diabetes

Type II Diabetes

Glucose

Insulin

Glucose

Treatment

  • maintain healthy diet and frequent exercise

  • medication only upon progression of disease state

  • Regular exercise can reduce and stop symptoms

Exocytosis

Insulin GLUT 4 Protein Vesicles

ExerciseGLUT 4 Protein Vesicles


Canadian connection

Canadian Connection

Frederick Banting & Charles Best

  • Nobel Prize – 1923

  • insulin isolation

    • tied off ducts to digestive tract

    • cell producing digestive enzymes shrivelled

    • only islets of Langerhans remained


Video testimonies

Video Testimonies

  • University of Alberta

    • developed islet cell transplant method

      Islet Transplant Animation

      Photo Journal

      News Feature


Stress regulation

Stress Regulation


Adrenal glands

Adrenal Glands

adrenal – “next to” the renal system

Two main sections:

  • adrenal cortex  long-term stress

  • adrenal medulla  short-term stress


Adrenal cortex

Adrenal Cortex

Long-term stress sends ACTH (adrenocorticotropic hormone)

Anterior pituitaryadrenal cortex

Adrenal cortex produces two types of hormones:

  • glucocorticoids

  • mineralcorticoids

ACTH


1 glucocorticoids

1. Glucocorticoids

  • class of steroid hormones for glucose regulation

  • specific example: cortisol

    What happens when you’re stressed out?

    • glucose not taken in by muscles

    • amino acids made into glucose

    • fat tissue broken down for energy


2 mineralcorticoids

2. Mineralcorticoids

  • class of steroid hormones for mineral regulation

  • specific example: aldosterone

    What happens when you’re stressed out?

    • blood pressure rises due to increase sodium & H2O reabsorption in kidneys


Adrenal medulla

Adrenal Medulla

Short-term stress detected by hypothalamus

Produces two hormones:

  • epinephrine (adrenaline)

  • norepinephrine (noradrenaline)

  • both compounds are examples of catecholamines, which are also neurotransmitters


Hormone structures

Hormone Structures

  • epinephrine

    • hydrophilic

  • norepinephrine

    • hydrophilic


Flight or fight response

Flight-or-Fight Response

What’s your response?

  • increased heart rate

  • increased breathing

  • blood vessel dilation  more O2 delivery

  • iris dilation  collect maximum visual information

  • these responses are induced by catecholamine release


  • Blood sugar regulation

    Stress

    Nerve

    signals

    Hypothalamus

    Spinal cord

    (cross section)

    Releasing

    hormone

    Nerve

    cell

    Anterior pituitary

    Blood vessel

    Adrenal medulla

    secretes epinephrine

    and norepinephrine.

    Nerve cell

    Adrenal cortex

    secretes

    mineralocorticoids

    and glucocorticoids.

    ACTH

    Adrenal

    gland

    Kidney

    (a) Short-term stress response

    (b) Long-term stress response

    Effects of epinephrine and norepinephrine:

    Effects of

    mineralocorticoids:

    Effects of

    glucocorticoids:

    1. Glycogen broken down to glucose; increasedblood glucose

    1. Retention of sodiumions and water bykidneys

    1. Proteins and fatsbroken down andconverted to glucose,leading to increasedblood glucose

    2. Increased blood pressure

    3. Increased breathing rate

    2. Increased bloodvolume and bloodpressure

    4. Increased metabolic rate

    5. Change in blood flow patterns, leading to

    increased alertness and decreased digestive

    and kidney activity

    2. Immune system may

    be suppressed


    Classwork homework

    Classwork/Homework

    • Section 8.2 – Pg. 383 #1-8,9


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