Hormonal Communication Part 2 Flashcards
What is blood glucose control an example of?
Negative feedback
What happens when blood glucose levels rise (hyper) to return them back to normal levels?
-Blood glucose level rises ->
-Beta cells respond by secreting insulin into blood ->
-Insulin binds to receptors on almost all cell membranes ->
-Blood glucose level lowered by one of 4 ways ->
-Return of blood glucose level to normal ->
-Beta cells reduce insulin secretion ->
-Normal level returns
What are the one in 4 ways for Hyperglycaemia?
-Respiration
-Glycogenesis
-Converted to lipid
-Cells absorb glucose
What happens when blood glucose levels fall (hypo) to return them back to normal levels?
-Blood glucose level falls ->
-Alpha cells respond by secreting glucagon into the blood ->
-Glucagon binds to receptors on hepatocyte membranes only ->
-Blood glucose level raised by one of two ways ->
-Return of blood glucose level to normal
-Alpha cells reduce glucagon secretion ->
-Normal level returns
What are the one in 2 ways for Hypoglycaemia?
-Gluconeogenisis
-Glycogenolysis
What is the first step in regulating blood glucose levels after beta cells recognise the rise in sugar levels?
Cells membrane has potassium and calcium ion channels
What is the second step in regulating blood glucose levels after beta cells recognise the rise in sugar levels?
The potassium ion channels are normally open so ions flow out
What is the third step in regulating blood glucose levels after beta cells recognise the rise in sugar levels?
When blood glucose concentration is high the glucose moves into the cell
What is the fourth step in regulating blood glucose levels after beta cells recognise the rise in sugar levels?
Glucose is metabolised to produce ATP
What is the fifth step in regulating blood glucose levels after beta cells recognise the rise in sugar levels?
ATP closes the potassium ion channels
What is the sixth step in regulating blood glucose levels after beta cells recognise the rise in sugar levels?
Accumulation of potassium ions alters the potential difference across the cell membrane so the inside become less negative
What is the seventh step in regulating blood glucose levels after beta cells recognise the rise in sugar levels?
The change in potential difference opens the calcium ion channels
What is the eighth step in regulating blood glucose levels after beta cells recognise the rise in sugar levels?
Calcium ions cause the vesicles of insulin to fuse with cell membrane, releasing insulin in exocytosis
What is the official name for Diabetes?
Diabetes Mellitus
What is Diabetes?
Inability to control blood glucose concentration
What are the 2 most common types of diabetes?
-Type 1
-Type 2
Type 1 Diabetes
-Called insulin dependent or early onset diabetes
-Body’s immune system attacks beta cells so insufficient insulin production
Type 2 Diabetes
-Called non-insulin dependent or late onset
-Reduced number of insulin receptors on muscle and liver cells with age
What is essential for the Heart Rate to do?
Respond to the needs of the individual
What homeostasis is HR responding to needs of individual?
Homeostasis of Blood Composition
What can variations occur to from this homeostasis?
-Heart Rate
-Strength of Each Beat
-Stroke Volume
What is the SA node responsible for?
Initiating the heartbeat
What is the set frequency of the SA node?
60-80 bpm
What is the SA node supplied with?
Nerves from autonomic nervous system which is divided into 2
What are the 2 parts of the autonomic nervous system?
-Sympathetic system
-Parasympathetic system
What do we call these 2 parts?
Antagonistic
What controls the autonomic nerves?
Medulla Oblongata
Medulla Oblongata
-Controls a cardiovascular centre
-Receives sensory information from receptors
-Sympathetic or parasympathetic systems are activated accordingly
What is an artificial pacemaker used for?
-Correct slow or disrupted heartbeats caused by disease or age
What is an artificial pacemaker?
Electronic devices implanted under the skin
What does a artificial pacemaker do?
Generates a pulse to one or more chambers of the heart
What 2 ways do artificial pacemakers generate a pulse?
-Some send regular pluses to the heart
-Some react to heartbeat and only send pulse when ventricles miss a beat
