Endocrine system: basics Flashcards
What is the nervous system divided into?
The peripheral (PNS) and central (CNS) nervous system
What is the CNS made of?
The brain and spinal cord
Label the diagram
What nerves take information into and out of the brain?
Afferent = into the brain (FYI remember it as info ‘arrives’ at the brain)
Efferent = out of the brain (remember it as info ‘exits’ the brain)
What are the two types of efferent nerves?
Somatic and autonomic neurons
What is the difference between Somatic and autonomic neurons?
Somatic are voluntary and control skeletal muscle, autonomic are involuntary and control cardiac muscle, smooth muscle and glands
What systems make up the autonomic system?
The sympathetic and parasympathetic systems
Label the diagram
Label the diagram
What do schwas cells do?
They myelinated individual axons or support multiple unmyelinated axons in the PNS
What do axon terminals do?
They interact with other nerves or tissue
Label the diagram, what is it?
A snapse
Where is the Synapse located?
At the end of axon terminals
How do the pre and post synaptic neuron communicate? What is communication between them?
By neurotransmitters
The pre-synaptic neuron causes the post-synaptic neuron to produce an AP
Explain the steps of how the pre and post synaptic neuron communicate
1 - An action potential goes down the pre-synaptic neuron
2 - The action potential changes the structure of the voltage gated Ca2+ channel allowing Ca2+ to go into the synaptic bulb
3 - The Ca2+ in the synaptic bulb causes the synaptic vesicles which contain neurotransmitters to bind to the surface of the pre-synaptic neuron and release the neurotransmitters
4 - The neurotransmitter then acts on the ligand gated post-synaptic receptors allowing Na2+ into the cell
5 - The influx of Na2+ depolarises the post-synaptic neuron causing an action potential
What is the alarm response associated with?
Exercise, emotion and excitement
What is the relaxation response associated with?
Repletion, rest and relaxation
What are the signs of an alarm response? What does each response allow?
(Learn at least 4 of them)
- Heart: has increased rate and force of contraction (increased physical capabilities)
- Skin: contraction of arrector pili muscle (i.e. hair stand up for increased cooling ability)
- Dilation of pupils (get more visual info in)
- Decrease salivation and digestion (energy directed to movement)
- construction in blood vessels especially in the skin (more blood for the necessary organs [i.e. muscles, brain…])
- dilation of the bronchi (get more O2 in)
- Increased blood sugar from liver (more energy to do work)
- Increased blood pressure and water retention (greater nutrient exchange)
What are the signs of a relaxation response?
(Learn at least 4 of them)
- Decreased rate and force of heart contraction
- Contraction of pupils
- Increased salivation
- Dilation of peripheral blood vessels
- Increased digestion
- Constriction of bronchi
What controls the alarm and relaxation responses?
Alarm = Sympathetic system
Relaxation = Parasympathetic system
What are the sensory inputs for autonomic and somatic nervous systems?
Autonomic: Mainly interceptors (i.e. internal sensing)
Somatic: Special and somatic senses
What are the controls of output for autonomic and somatic nervous systems?
Autonomic: Involuntary from the limbic system, hypothalamus, brain stem and spinal cord
Somatic: Voluntary from the cerebral cortex
What are the motor neurone pathways for autonomic and somatic nervous systems?
Autonomic: Two neuron pathway (i.e. pre and post ganglion)
Somatic: One neuron pathway
What are the neurotransmitters for autonomic and somatic nervous systems?
Autonomic: Acetylcholine and norepinephrine
Somatic: Acetycholine
What are the effectors of the autonomic and somatic nervous systems?
Autonomic: Smooth and cardiac muscles and glands
Somatic: Skeletal muscles
What does acetylcholine (ACh) control in the autonomic system?
Preganglionic axons, postganglionic parasympathetic, postganglionic sympathetic to sweat glands
What does norepinephrine (NE) control in the autonomic system?
Postganglionic sympathetic fibres that don’t go to the sweat glands
How does a one or two neuron pathway change how the autonomic and somatic pathways operate?
Two neuron pathway in the autonomic system means that a single signal can go and influence many different systems. A single huron pathway in the somatic system means each signal influences only one part of the body
Where is ACh and NE used in the somatic and autonomic systems?
Autonomic: ACh is used between all preganglionic neurons. ACh is used in post ganglionic neurons connected to sweat glands and NE is used in the postganglionic neuron for effector cells
Somatic: ACh used at the end of the axon terminal to the effectors
Label the diagram
What are cholinergic cells? Where would you find them?
Nerve cells that use ACh as a primary neurotransmitter
As part of the preganglionic nerve and postganglionic nerves going to sweat glands in the autonomic system and the motor neuron in the somatic system
What are adrenergic cells? Where would you find them?
Nerve cells that use NE as a primary neurotransmitter
As part of the postganglionic nerve going to effector cells in the autonomic system
What are muscarinic receptors?
The ACh receptor on the effector cell/gland
What are adrenergic receptors?
The NE receptors on effector cells
What are the effector cells in the somatic and autonomic system?
Somatic: Skeletal muscle
Autonomic: Smooth and cardiac muscle and glands
What is the function of the hypothalamus?
- Control internal organs via autonomic nervous system and pituitary galnd
- regulate behaviour and circadian rhythms
- Controls body temperature
- Regulates eating and drinking
Where is the hypothalamus?
What is the endocrine system?
A series of glands throughout the body that secret hormones throughout the body
Label the diagram. What organs make up the trunk of the endocrine system?
Hypothalamus, pituitary and adrenal gland
What are hormones?
Molecules that affect the function of other cells
What are the two types of hormones? What are the differences between them?
Paracrine hormones: Hormones that are produced by a cell to affect OTHER cells
Autocrine hormones: Hormones that are produced by a cell to affect ITSELF
What is the process of controlling hormone release?
1 - Hormone is synthesised and either stored or released
2 - If released it goes into the blood
3 - It affects the target cell
4 - The grooms is broken and/or excreted
5 - A feedback signal is created (i.e. target cell produces chemical signal, normally a negative feedback loop back to 1 which causes deactivation of hormone production)
What are the two types of hormone solubility?
Either lipid or water soluble
What are the major differences between lipid and water soluble hormones?
- Lipid: requires transport protein when in the blood, diffuses through cell membrane, acts directly on the nucleus to initiate DNA synthesis with long term
- Water: dissolves in the blood, acts on membrane receptors on the surface, creates signalling proteins which
Label the diagram showing the process of a lipid soluble hormone acting on a cell
Label the diagram showing the process of a water soluble hormone acting on a cell
How do lipid and water soluble hormones affect cellular activity differently?
Water = change in behaviour of a cell (i.e. changes how active a protein is), lipid = change in cellular activity (i.e. what proteins are present)
