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HUBS1416 Exam Questions With Complete Solutions Where is Gastrin secreted stomach What is the function of Gastrin Stimulates stomach activity What does CCK stand for cholecystokinin Where is CCK secreted small intestine What is the function of CCK Stimulates secretion of pancreatic enzymes, contraction of gallbladder & inhibits gastric emptying Where is secretin secreted Small intestine (if material entering SI is acidic) What is the function of secretin Stimulates the secretion of HCO3- (bicarbonate) Where is Insulin secreted from beta cells of pancreas
What is the function of insulin
- Stimulates storage of glucose in liver and muscle tissue
- Stimulates reuptake of glucose when blood sugar is high - lowering blood sugar Where is Glucagon secreted alpha cells of pancreas What is the function of Glucagon Stimulates release of glucose from liver when blood sugar is low, raising blood sugar levels How is leptin produced Produced by adipose (fat) tissue What does Leptin do Suppresses appetite as it's levels increase What happens to leptin levels when body fat decreases levels fall and appetite increases What secretes hormone PYY (peptide YY) Secreted by the small intestines after a meal What does hormone PYY do Acts as an appetite suppressant that counters the appetite stimulant ghrelin
- Decrease with age & decrease with starvation
- increase with increasing activity, temperature, thyroid hormone level, stress, anxiety and in pregnancy
- Faster in men and in larger people What does metabolism provide energy for
- Homeostasis
- Growth, maintenance and repair
- Secretion and contraction What are anabolic reactions Building up of substances from simple to complex Do anabolic reactions require energy input Yes What is an example of an anabolic reaction amino acid monomers are bound together in a reaction to form protein polymers What is a catabolic reaction Decomposition of a complex substance to a simpler substance. These actions release energy What is an example of a catabolic reaction Glycogen stored in the liver, becomes glucose when energy is needed
What are the four mechanisms of nutrient absorption
- Active transport
- Passive diffusion
- endocytosis
- facilitative diffusion Where does most nutrient absorption occur villi & microvilli with a little in the stomach and large intestine How are carbohydrates absorbed Broken down into glucose & absorbed through the small intestines wall How is carbohydrate used for energy Enters bloodstream and is eaten up by cells in tissues for energy how many kj of energy does 1g of carbohydrate make 1g = 17kj energy (4cal) What is the metabolic fate of fats Metabolise to produce glycogen, and what isn't needed is stored in fat cells as triglycerides How is fat used for energy -- from food is broken down into fatty acid and travels in the blood, it can then be captured by hungry cells How many kj of energy does 1g of fat make
A protein in an inactive form. Must be activated by hydrochloric acid. Once activated it is a protease that does chemical digestion of proteins What is the role of Gastric Lipase in gastric juice Fat and lipid digestion What is the role of intrinsic factor in gastric juice necessary for the absorption of vitamin B12. Where is vitamin B12 absorbed Colon What is the purpose of vitamin B red blood cell production What is in pancreatic juice
- Sodium bicarbonate and Enzymes What are the enzymes in pancreatic juice
- Amylase
- Lipase
- proteases
- nucleases What does Amylase in pancreatic juice break down Carbohydrates What does Lipase in pancreatic juice breakdown
lipids what does proteases in pancreatic juice break down proteins what does nucleases in pancreatic juice break down nucleic acids Why are proteases in an innactive form before after being produced so they don't break down our own body cells and our body proteins that we need to function Where are proteases activated Lumen What is the role of sodium bicarbonate in pancreatic juice neutralises stomach acid What is in bile
- Bile salts
- Bile pigments (e.g billirubin)
- Cholesterol What is the role of bile salts in bile Emulsify fats to allow lipase to get at the fat droplets What is the role of bile pigments in bile
Produces hormones including insulin, glucagon, somatostatin and pancreatic polypeptide What causes obesity generally Higher energy intake then energy expenditure What is segmentation Is a slow process that involves contracting circular muscles in the digestive tract. Chyme is pushed back and forth within the adjacent sentiments of the intestine. It is a mixing movement. What is peristalsis A wave of muscle contractions, that forces food bolus to move down the GI tract What is the voluntary phase of swallowing Tongue and cheeks push the blows back towards the pharynx What is the involuntary phase of swallowing Pharyngeal muscles propel the bolus into the oesophagus, it is pushed down the oesophagus by peristalsis What inhibits the stomach The arrival of chyme in the small intestine - both the nervous and endocrine system work to slow down gastric activity and reduce acidity when the chyme starts to come through the duodenum
Why do we only want a small amount of chyme at a time in the small intestine So that we allow it time and access to all of the enzymes to our partially digested nutrients, so that we can completely digest them How are proteases activated in the duodenum By brush border enzymes (enterokinase) lining the wall of the small intestine How does the arrival of chyme in the duodenum trigger hormonal responses that coordinate intestine and stomach functions
- Chyme enters the duodenum from the stomach
- Fatty and amino acids in chyme stimulate the release of CCK from the duodenal cells
- Acid in chyme stimulates the release of secretin from duodenal cells into bloodstream
- CCK causes the exocrine pancreas to secrete enzyme-rich juice
- Secretin causes exocrine pancreas to secrete bicarbonate-rich juice and inhibits further gastric acid secretion and gastric motility
- CCK stimulates the liver to increase bile production
- CCK causes gallbladder to contract & sphincter of Oddi to relax > bile enter duodenum
Produces digestive hormones trysin & chymotrypsin (proteases), amylase and lipase. Produces bicarbonate to neutralise acid How is glucose utilised in the DS
- Glucose comes in from the small intestine (in the hepatic portal vein)
- Insulin turns glucose to glycogen and glucagon turns glycogen to glucose
- Some glucose is converted to glycogen and stored
- Glucose lages the liver in the hepatic vein What is the purpose of glucose
- It is used to produce energy for cells (ATP)
- It is used to maintain blood glucose level in the normal range
- It is converted to glycogen and stored in muscles
- It is converted to fat and stored in adipose tissue List the different parts of a neuron
- Cell body (soma)
- Dendrites
- Axons
- Axon terminal
- Myelin sheath What is the role of the soma of a neuron
Decides if we need to send the information on or if we need to stop sending the information. Also produces proteins needed for other parts of the neuron. What is the role of the dendrites of a neuron Sense and receive information from other neurons. Include receptors for things such as cold, pain and pressure. (INPUT) What is the role of the axons of a neuron Long nerve fibres that are capable of propagating electrical impulses known as action potential through them from the cell body. Can also be a nerve impulse conduction area. (INTEGRATION) What is the role of the axon terminals of a neuron Nerve endings that make synaptic contacts with other neurons and effector cells. They contain various kinds of neurotransmitters What is the role of the myelin sheath of a neuron The insulating cover of axons which increases the speed at which electrical impulses travel along the neuron (not all neurons have this) What are neurotransmitters chemicals with cover the message across the synaptic space What is membrane potential
depolarised
- When the action potential reaches its peak, sodium channels close & potassium (K+) channels open. Which allows K+ to flow out of the cell. The loss of positive potassium ions, makes the inside of the cell negative again. This is depolarisation.
- Action potentials are spread across synapse by synaptic transmission. The arrival of the action potential at the axon terminal triggers the release of a neurotransmitter into the synapse. The neurotransmitter then diffuses across synapse & binds to receptors on the membrane of the next cell, creating another action potential. How is the concentration gradient of the membrane potential maintained Active transport (using ATP) of sodium ions out of the cell and potassium ions in A At rest are sodium channels or potassium channels open Potassium Process of synaptic transmission
- neurotransmitter release - arrival of action potential at the axon terminals triggers the release of neurotransmitter into the synapse
- Receptor activation - the neurotransmitter diffuses across the synapse and binds to receptors on the membrane of the next cell
- Termination of the message - the neurotransmitter is
inactivated by being transported back into the icon terminal and by enzymatic breakdown What are the glial cells of the CNS
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal cells What are the glial cells of the PNS
- Schwann cells
- Satellite cells What is the purpose of the astrocytes
- Physically support neurons & repair damaged tissue
- Astrocyte processes wrap around capillaries and form the Blood Brain Barrier
- Help regulate ionic composition of ECF
- Removes excess neurotransmitters What is the purpose of Oligodendrocytes
- Contact exposed surface of neurons
- Form a myelin sheath along axons in the CNS What is the purpose of Microglia
- Help protect CNS via phagocytosis of waste debris and pathogens
what is the internal grey matter in the spinal cord cell bodies How many pairs pf spinal nerves are there 31 how many pairs of cranial nerves are there 12 What is the function of the somatic nervous system
- controls skeletal muscle, joints, tendons and skin
- things we involuntarily control What is the purpose of the autonomic nervous system
- controls involuntary activities via glands and organs
- can be divided into 3 parts; sympathetic. parasympathetic & enteric What is the purpose of the sympathetic nervous system (fight or flight)
- controls short lived behaviour
- e.g increased HR & respiration rate, adrenaline released, slows or turns off non-essential processes What is the purpose of the parasympathetic nervous system (rest and digest)
- maintains stable body functioning in normal conditions
What is the purpose of the enteric nervous system Mesh work of nerve fibres that innervate the visceral (GI tract, pancreas and gallbladder) What is the purpose of the motor division of the nervous system Efferent responses going out from the NS to the environment What are somatic motor functions
- Movement of skeletal muscles
- Movement of facial muscles What are autonomic motor functions
- Movement of smooth muscles
- gland activity What is the purpose of the sensory division of the nervous system Afferent Stimuli coming in to the NS from the environment Somatic sensory functions
- Senses i.e touch, taste, smell, hearing, vision & balance
- Joint positions and muscle length (stretch contraction) Autonomic sensory functions
