control coordination and feedback n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Control, Coordination and Feedback PowerPoint Presentation
Download Presentation
Control, Coordination and Feedback

Loading in 2 Seconds...

play fullscreen
1 / 28

Control, Coordination and Feedback - PowerPoint PPT Presentation


  • 80 Views
  • Uploaded on

Control, Coordination and Feedback. Blood glucose control. What is glucose? Why is glucose in the blood? Where does it come from? Where does it go? What is it there for? How much is there? How do you measure it? When does the concentration increase? When does the concentration decrease?.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Control, Coordination and Feedback' - arissa


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
blood glucose control
Blood glucose control
  • What is glucose?
  • Why is glucose in the blood?
  • Where does it come from?
  • Where does it go?
  • What is it there for?
  • How much is there?
  • How do you measure it?
  • When does the concentration increase?
  • When does the concentration decrease?
glucose concentration
Glucose concentration

80 to 120 mg 100 cm-3 blood

This is the ‘normal’ range

The concentration fluctuates

Below 60 mg 100 cm-3 – coma

Above 180 mg 100 cm-3 exceeds renal threshold and glucose appears in the urine

blood glucose
Blood glucose

What goes wrong when the concentration decreases?

What goes wrong when the concentration increases?

blood glucose1
Blood glucose

What goes wrong when the concentration decreases too far?

Hypoglycaemia

The symptoms associated with low blood sugar are:

tiredness, confusion, dizziness, headaches, mood swings, muscle weakness, shaking

blood glucose2
Blood glucose

What goes wrong when the concentration increases too far?

Hyperglycaemia

The symptoms include:

Excessive thirst; frequent urination;

fatigue; unexplained weight loss;

vision problems, such as blurring;

increased susceptibility to infections such as thrush.

blood glucose concentration
Blood glucose concentration
  • Keep within narrow limits
  • Corrective action if it increases
  • Corrective action if it decreases
  • Control mechanism needs to respond to fluctuations
    • Negative feedback
    • reduces the difference between actual and ideal / norm / set point
feedback system
Feedback system
  • Input
  • Receptor
  • Control centre
  • Effector(s)
  • Communication system
  • Corrective actions
  • Negative feedback
liver cells
Liver cells

Binucleate cell

central vein

liver cell1
Liver cell

protein metabolism

lipid metabolism

carbohydrate metabolism

carbohydrate metabolism
Carbohydrate metabolism
  • glucose absorbed across membrane by facilitated diffusion
  • glucose stored as glycogen
  • glucose  glucose 6 phosphate
  • glucose 6 phosphate  glucose 1 phosphate
  • glucose units added onto end of glycogen molecule (glycosidic links)
  • glycogen synthetase
carbohydrate metabolism1
Carbohydrate metabolism
  • glycogen broken down to glucose
  • glucose 1 phosphate molecules formed
  • glucose phosphorylase
  • glucose 1 phosphate  glucose 6 phosphate
  • glucose 6 phosphate to glucose
  • glucose diffuses out of cell through protein carriers
glucose storage
Glucose storage
  • glucose concentration in blood increases
  • beta cells in pancreas release insulin
  • insulin stimulates liver cells to store glucose as glycogen
  • insulin stimulates lipid synthesis
  • insulin stimulates protein synthesis
  • insulin helps to conserve resources
islet of langerhans
Islet of Langerhans

endocrine tissue

exocrine tissue

alpha cells
Alpha cells

Beta cells

secondary messengers
Secondary messengers
  • Glucagon and insulin are both proteins
  • Do not cross membranes
  • Signalling transduction at cell membrane
  • Secondary messenger produced inside membrane
  • 2o messenger transmits signal to enzymes within cytoplasm
cyclic amp
Cyclic AMP
  • Produced just inside cell membrane
  • ATP  cyclic AMP
  • Catalysed by Adenylate cyclase
  • Cyclic AMP combines with a protein
  • Starts a ‘chain reaction’ following stimulation by glucagon
amplification
Amplification
  • Quick response required from many enzymes
  • Signal is amplified
  • Chain reaction:

A  B  C  D

  • Enzyme cascade
  • Final enzyme converts glycogen  glucose
modern technology
Modern technology

Biosensor Insulin mini-pump