Week 1 Neuroendocrinology ✅ Flashcards
What is an action potential?
Electrical impulse - language of the nervous system
What structures does the CNS consist of?
Brain and spinal cord
Give 3 examples of stimuli neurons
Physical, chemical, thermal
What are supporting cells?
Non-excitable cells, “neuroglia”
5x more abundant than neurons
What is the function of dendrites?
Receive impulse and transmit to the post-synaptic neuron
What is the function of the axon hillock?
Generate impulse in neuron from local potentials
Where is the axon hillock located?
Summation Zone
What are the 3 types of neurons and what is their function?
Afferent - sensory
Efferent - motor
Interneurons - integratons
Where are the nerve terminals located?
Output zone
What are the 4 nerve zones?
Input
Summation
Conduction
Output
What is a unipolar nerve cell?
1 axon
1 nerve process
Not human (e.g. flies)
What is a bipolar nerve cell?
1 axon
1 dendrite
What is an example of a bipolar nerve cell?
Olfactory nerve
Retina
Ear nerves
What is a multipolar cell?
1 axon
Multiple dendrites
What is an example of a multipolar cell?
CNS, autonomic nervous system
What is a pseudounipolar cell?
Like bipolar neurones
E.g. sensory neurons
What is the function of an astrocyte?
Connect blood vessels to neuron
Give an example of where an astrocyte is located
Blood brain barrier
What is the function of microglia?
Protect CNS neurons by phagocytosis
How many ventricles are there in the brain?
4
What does the Corpus callosum do?
Connect the 2 cerebral hemispheres
What is the function of ependymal cells?
They line the ventricles of the brain to protect them and produce CSF
What is the absolute refractory period?
Time when Na channels open, close and K channels open - the membrane CANNOT RESPOND TO FURTHER STIMULATION
What is the relative refractory period?
When K channels close and Na/K channels return to normal state, the membrane CAN ONLY RESPOND TO LARGER STIMULI
What are the steps of the refractory period?
- Resting membrane potential of cell is at -70mV
- Cell is stimulated and charge becomes more positive, Na channels open
- Membrane becomes +30mV, Na channels close and K channels open
- Cell repolarises and charge goes below resting potential of -70mV - K channels close
- Cell returns to -70mV
What is the resting membrane potential of a cell?
-70mV
What is the threshold of a neuron?
Minimum stimulus to create action potential
How does a cell repolarise to normal resting membrane potential?
Restored by sodium potassium pump
What is saltatory conduction and which cells does this apply to?
Faster conduction - jumps between nodes of ranvier
Occurs in myelinated cells
What is the major extracellular cation?
Sodium
What is the major intracellular cation?
Potassium
What are the 3 meninges of the brain?
Dura mater
Arachnoid mater
Pia mater
What 3 parts of the brain make up the brain stem?
Forebrain
Midbrain
Hindbrain
What structures make up the forebrain?
Cerebrum and diencephalon
What structures make up the hindbrain?
Cerebellum, pons and medulla
What is the limbic system responsible for?
Emotions
What is the frontal lobe responsible for?
Motor - movement in the body
What is the parietal lobe responsible for?
Sensory cortex
What is the occipital lobe responsible for?
Visual cortex
What is the temporal lobe responsible for?
Auditory cortex, olfactory and gustatory
What structures make up the cerebral cortex?
Frontal, parietal, occipital and temporal lobes
Name the structures of the brain from the cerebrum downwards
Cerebral cortex
Basal ganglia
Thalamus
Hypothalamus
Cerebellum
Brain stem
What is the basal ganglia responsible for? What condition affects this area?
Coordination, planning of movement
Parkinson’s disease
What is the thalamus responsible for?
Sensory relay system from periphery
What is the hypothalamus responsible for?
Homeostasis
What is the cerebellum responsible for?
Planning, programming and coordination
What is the brain stem responsible for?
Heart rate centre
respiratory rate
blood vessel diameter
(cranial nerves)
How many cervical vertebrae are there?
7
How many thoracic vertebrae are there?
12
How many lumbar vertebrae are there?
5
How many sacral vertebrae are there?
5
How many spinal nerves are there?
31
How many cranial nerves are there?
12
What is the difference between sulcus and grus?
Sulcus is a V shape
Grus is a n shape
What is the Bell Magendie law?
Dorsal root is always sensory
Ventral root is always motor
What is the role of the spinal cord in reflexes?
Integrating centre (pre-ganglionic)
What is the only hormone in positive feedback?
Oxytocin
What are the 3 types of synapse?
Axo-dendritic
Axo-somatic
Axo-axonic
What is a ganglion?
Collection of nerves in somatic and autonomic branches of PNS
What is the neurotransmitter of the sympathetic nervous system?
Acetylcholine and noradrenaline
What is the neurotransmitter of the parasympathetic nervous system?
Acetylcholine
What is the difference between exocrine and endocrine glands?
Exocrine secretes into ducts
Endocrine secrete into blood - ductless
What is an example of an exocrine gland?
Salivary glands, parotid gland
Is the pancreas an exocrine or endocrine gland?
Both. Pancreatic juice is the exocrine part
What are the gonads?
Ovaries and testicles
Which gland releases melatonin?
Pineal gland
What hormones does the thyroid gland release?
T3 and T4
What hormone does the parathyroid release?
Parathyroid hormone
What hormone does the thymus gland release?
Thymosin hormone
(mature T lymphocytes)
What hormones does the pancreas release?
Insulin and glucagon
What hormones does the ovaries release?
Oxytocin, Oestrogen
What hormone does the testicles release?
Testosterone
What are examples of steroid hormones?
Sex hormones, adrenal cortex hormones
What are examples of amine hormones?
Melatonin, thyroid hormones
What are examples of protein hormones?
Insulin, glucagon
What are examples of glycoprotein hormones?
FSH, TSH
What are examples of eicosanoid hormones?
Prostaglandins
What are examples of peptide hormones?
Oxytocin, Vasopressin
How do hormones work?
Bind to receptor and enter cell
Initiate second messenger system
Stimulate protein release
What does autocrine mean?
Acts on the same cell
What does paracrine mean?
Acts on nearby cells
What does endocrine mean?
Acts on cells via transport in the blood
How many cervical nerves are there?
8