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EILANDJES VAN LANGERHANS (DUTCH)
α-cellen produceren glucagon
glycogeen is een opslagmiddel van glucose
bij productie van glucagon, wordt glycogeen omgezet in glucose (= GLYCOGENESE)
het VERHOOGT dus de bloedsuikerspiegel
adrenaline en cortisol verhogen ook de bloedsuikerspiegel.
Β- cellen produceren insuline
een tekort aan insuline leidt tot DIABETES (een abnormaal
hoge bloedsuikerspiegel)
- Wanneer er geen insuline in het lichaam wordt
gemaakt, spreekt men van diabetes type 1.
- Wanneer voldoende insuline gemaakt wordt, maar
lichaamscellen onvoldoende op insuline reageren,
spreekt men van diabetes type 2.
het VERLAAGT de bloedsuikerspiegel
Inname van veel suikerhoudende dranken leidt tot productie van insuline zo wordt de
bloedsuikerspiegel weer verlaagd.
Insuline stimuleert de opname van glucose door cellen
Stimuleert de synthese van glycogeen
Remt de glycogenese
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!!!! Na+ = Sodium
INDEPENDENT // DEPENDENT VARIABLE
For example, a biologist notices that a birds
feeds more in the winter than in the summer.
She generates a hypothesis that cold
, temperatures cause birds to increase their food intake. To test her hypothesis, she designs an
experiment in which she keeps birds at different temperatures and monitors how much they eat.
In her experiment, temperature, the manipulated element, is the INDEPENDENT variable. Food
intake, which is hypothesized to be dependent on temperature, becomes the DEPENDENT
variable.
Essential: control group!
If the experiment supports the hypothesis that cold causes birds to eat more, then the
experiment should be repeated to ensure that the results were not an unusual one-time
event. This is called replication. When the data support the hypothesis in multiple
experiments, the hypothesis may become a working model and later on a scientific theory.
EXAMPLE: Islets of Langerhans
- Paracrine: glucagon increasing [glucose]
Glucagon is released by α-cells, affects β-cells
- Endocrine: releasing glucose in the blood stream & fat storage
Increasing of glucose is also affecting many other organs!
EXAMPLE CCK
- Released in the gut after eating a meal
- Paracrine: releasing of digestive enzymes
- Endocrine: releasing insulin by β- cells, because food is coming and to keep
homeostasis you need insulin to decrease the [glucose]
! Pheromones are hormones used for communication; mostly for reproduction
EXAMPLES:
A silk moth, female, releases pheromones in the air the male can sense in this way where
the female is and can fertilize her
- Androsterone: signal for a reproduction animal that is ready to mate
A vomeronasal organ can detect different pheromones
! It is always up to the brain to use or ignore a signal
A factor is released a receptor sensed it brain can ignore or use it
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NERVOUS SYSTEM
Central Nervous System (CNS)
o Brain
o Spinal cord
! Neurons that entirely lie within the CNS are knows as interneurons
Peripheral Nervous System (PNS)
o Located outside the skull and spinal cord
o Serves to bring information into the CNS and carries out signals of the CNS
It consists of two components:
- Somatic nervous system
Afferent nerves (sensory)
Efferent nerves (motor)
Afferent and Efferent are related to the words Afflux and Efflux, respectively. Afflux means flow
towards an area or point, Efflux means outward flow from an area.
Spinal cord: Afferents to the spinal cord carry sensory information from the body to the spinal cord;
efferents from the spinal cord carry information from the spinal cord to the muscles and other
organs.
, Cerebellum: Afferents carry information from areas of the CNS to the cerebellum, efferents carry
information from the cerebellum out to the brain stem and further.
- Automatic nervous system
Sympathetic system (fight-flight)
activation of the body leads to increased activity of the sympathetic
nervous system // increase in heart rate and blood pressure,
mobilisation of the energy substrates glucose and free fatty acids from
liver and white adipose tissue (catabolic processes)
Parasympathetic system (rest)
the parasympathetic nervous is activated when the body returns to the
resting condition (rest and digest) // reduction in heart rate, vasodilation,
storage of energy substrates in glycogen, fat and muscle (anabolic
processes)
! the autonomic nervous system innervates those systems that cannot be controlled by the conscious
brain such as heart, smooth muscle, blood vessels, most visceral organs (liver, pancreas) and all
endocrine glands
! only anticipating makes the gut already vesicular, so the brain must control this.
Claude Bernard: the brain controls the body.
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NEED TO KNOW:
- Neurotransmitter Acetylcholine:
which is mainly involved in the impulse transfer from nerve cells
to skeletal muscle cells.
Regulation of peristalsis
A deficiency of acetylcholine causes myasthenia ( a rarely auto-
immune disease that causes weakness of muscles)
- Nicotinic
cholinergic receptors: refers to a neurotransmitter that releases
acetylcholine in a synaps
- Noradrenalin (neurotransmitter & hormone)
Causes a permeability in the membrane
- Adrenalin
Effects the sympathetic system
! a chaperone proteins: proteins that assist the covalent folding or unfolding and the assembly or
disassembly of other macromolecular structures.
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