Review posters 14/05/2016 Flashcards
Process of glycogen synthesis
Glucogenesis
Process of glycogen synthesis from non-carbohydrate pre-cursors
Gluconeogenesis
Process of glycogen breakdown
glycogenolysis
Where is glycogen stored?
The liver and muscles
What is the difference between the two places glycogen is stored?
The muscle cell has to use to glycogen that is broken down there, whereas the liver can release it into the bloodstream.
When is glycogen broken down?
Between meal times.
How are blood sugar levels maintained?
Just after a meal- blood sugar levels are at their highest.
Also inbetween meals- glycogen is released to keep blood sugar levels up.
At times like breakfast when you haven’t eaten in a while- gluconeogenesis comes into play.
What is glucogenin and why do you need it?
Glycogen synthase cannot make glycogen without an existing chain being present. Therefore you need glucogenin which acts as a starting point at the centre of glycogen. It has catalytic activity which allows it to add small amounts of glucose onto it.
What is UDP glucose?
This is activated glucose. Urine disphosphate with a glucose attached to it. The bond between glucose and phosphate contains high energy- this is used to transfer glucose.
Glycogen synthase can introduce 1-6 branches. True or False
False
Which enzyme introduces branches into glycogen?
Branching enzyme
What catalyses glucogenolysis?
Glycogen phosphorylase
What is glycogen converted too in glucogenolysis?
Glycogen is converted too glucose-1-phosphate. This can then be converted into glucose-6-phosphate.
What happens in the liver in glucogenolysis?
Glucose-6-phosphate is dephosphorylated to glucose which can then be released into the blood via GLUT2.
What is the fate of glucose-6-phosphate in muscle?
It undergoes glycolysis and releases energy.
How is glycogenolysis stimulated and at which part of the cycle?
Adrenaline and cortisol stimulate glycogen phosphorylase.
Name the precursors used in gluconeogenesis
Lactate, amino acids and glycerol
Describe each of the precursors
Lactate- derived from anaerobic respiration
Amino acids- glucogenic amino acids. Derived from muscle protein.
Glycerol- from triglycerides in adipose tissue.
Describe gluconeogenesis
Extremely energy consuming making of new glucose.
Essentially the reverse of glycolysis- needs specific enzymes to get round the irreversible reactions.
Classes of amino acids
Ketogenic- can’t be used in gluconeogenesis
Glucogenic- can be used in gluconeogenesis
What happens to glucogenic amino acids?
They are either converted to pyruvate and then to glucose or enter the TCA cycle and are converted to oxaloacetate then glucose.
Hormonal regulation of gluconeogenesis
Glucagon - increases gluconeogenesis
Inhibits glycolysis
Insulin- decreases gluconeogenesis
Stimulates glycolysis
What occurs in the embryonic stage of lung development?
Respiratory diverticulum forms
Initial branching to give lung, lobes and segments
What occurs in the Psuedoglandular stage of lung development?
Formation of terminal bronchioles
What occurs in the cannicular stage of lung development
Terminal sacs (alveoli) form.
What occurs in the alveolar stage?
maturation of the alveoli
From which layer does the gut evolve?
Primarily endoderm and some visceral mesoderm.
Which layer does the heart arise from?
Visceral mesoderm.
What does the truncus arteriosus give rise too?
Aorta and pulmonary trunk
What does the bulbus cordis give rise too?
The right ventricle and outflow tract
What does the ventricle give rise too?
The left ventricle
What does the atrium give rise too?
The right and left atrium
What does the sinus venosus give rise too?
The right atrium and coronary sinus.
What does the vittelline vein do?
Drains yolk sac
What does the umbilical vein do?
Drains placenta
What does the cardinal vein do?
Precursors for systemic venous system.
Ductus venosus
Directs oxygen rich blood from the placenta to the IVC bypassing the liver
Foramen ovale
Directs oxygen rich blood from the right atrium to the left atrium so it bypasses the lungs
Ductus arteriosus
Directs deoxygenated blood from the pulmonary artery to the descending aorta as it goes to the placenta