Nervous system! Flashcards
Define neuroscienece
Study of the nervous system
Name three different approaches to neuroscience
E.g. cellular/molecular, behavioural, cognitive, computational, clinical
Define Dale’s Law
that each neuron has a specialised function
What are neuronal fibres
Outgrowths of neurons
What is the neural unit?
The fact that the brain is made up of individual neurons that contain specialized features.
Name the three basic parts of a neuron
The dendrites, the cell body, and the axon
How many layers is the human neocortex made up from?
6
Name the two types of responses a neuron can exhibit depending on the stimulus
Tonic (repeated triggering) and Phase (a single firing)
True of false: Potassium moves freely through channels whilst sodium is tightly regulated.
True
What does the refractory period ensure?
Uni-directional movement
How do the nodes of Ranvier affect voltage speed?
They increase the speed as they allow the signal to “jump” down the axon.
Name two ways in which transmission can be sped up
Giant axons and myelination.
What happens when myelin is lost/degrades? Give an example.
A range of autoimmune diseases can develop such as multiple sclerosis
What stimulates the release of transmitters from intracellular vesicles?
Voltage-gated calcium channels in the presynaptic neuron
What do ionotropic and metabotropic mean in terms of signalling receptor speed?
Ionotropic = fast and metabotropic = slow
What does the hypothalamus control? Name the three things.
Endocrine regulation, autonomic function, and limbic function.
Define the neural doctrine
The concept that the nervous system is made up of discrete individual cells
What is the major biological difference seen in the human brain when compared to other mammals?
Much larger and more developed frontal cortex
Name the four main areas of the human brain
Telencephalon, Diencephalon, Mesencephalon and the cerebellum
What makes up the telecephalon?
Cortex and the deeper structures of the cerebrum
What makes up the diencephalon?
The thalamus and the hypothalamus
What makes up the Mesencephalon?
The midbrain, the pons and the medulla
Where are the most sophisticated functions of our brain located?
The top and front of our brains.
What is the function of cerebrospinal fluid?
To insulate the brain
What does the blood-brain barrier ensure?
That only essential molecules pass into the brain
What are the two branches of the autonomic system?
Sympathetic and parasympathetic
True or false: The parasympathetic and sympathetic systems work one at a time.
False- they are both constantly active
Where do preganglionic sympathetic and parasympathetic fibres originate from? What do they both secrete?
Sympathetic = spinal cord. parasympathetic = brain and lower spinal cord. Both secrete acetylcholine.
What do postganglionic sympathetic and parasympathetic fibres secrete? What are the specific names for both types of fibres?
sympathetic = norepinephrine and adrenergic. parasympathetic = acetylcholine and cholinergic
What does the Adrenal cortex secrete?
Mineralocorticoids and glucocorticoids
What arteries supply the brain with blood?
The internal cortical arteries and the vertebral arteries.
What doe the Internal Carotid arteries and the vertebral arteries combine to form?
The circle of Willis
What is a stroke?
The interruption of blood flow to the brain causing cell death.
What do stroke symptoms and aftermath depend on?
Location of stroke, type of stroke and time before treatment.
True or false: the endocrine system is uni-directional
False - it is bi-directional
What are the two types of signals that can be recieved by a postsynaptic neuron?
Excitatory and inhibitory
Briefly describe how a neuroendocrine signal is transmitted (presynaptic neuron to target cell.)
presynaptic neuron –> postsynaptic neuron –> bloodstream –> target cell.
What are endocrine cells specialized for?
synthesis, storage, release
Where are receptors for hormones located within cells?
The cytoplasm or cell membrane
Name the three CNS endocrine glands
Pineal gland, hypothalamus, pituitary gland
How do most nuclei in the hypothalamus communicate with the endocrine system?
Via the pituitary gland
What major hormones are released from the ANTERIOR pituitary gland?
Growth hormone (gnRH), LH and FSH
What 2 major hormones are released from the posterior pituitary gland?
Vasopressin and oxytocin
True or false: Oestrogen operates with both negative and positive feedback loops?
True
What is the function of Leydig cells and where are they found?
Found in the seminiferous tubules and produce testosterone in response to LH
What is the function of Sertoli cells and where are they found?
Found in the seminiferous tubules and stimulate sperm maturation.
What do theca cells produce?
Androstenedione
at do Granulosa cells produce?
Oestrogen
What are the two parts of the adrenal gland?
The adrenal cortex and the adrenal medulla
What responses do the adrenal medulla and cortex stimulate?
Medulla = fight or flight response. Cortex = stress response
What does the pineal gland secrete?
Melatonin
What determines if an endocrine cell can synthesise a hormone or not?
Which enzymes it produces
What governs most sex differences?
Aromatase levels and distribution
define stress
Anything that puts the body out of homeostatic balance
What is the process of allostasis?
The maintenance of stability through physiological or behavioural change.
Describe the relationship between stress and health
As stress levels increase, health worsens
How is the circadian rhythm regulated?
Through environmental factors
What is the suprachiasmatic nucleus?
A group of specialised cells located in the hypothalamus
What does the suprachiasmatic nucleus activate?
Secretion of melatonin from the pineal gland
How is melatonin supressed and how is it measured?
Melatonin is supressed by light exposure and is measured through the blood or saliva
Name two negative consequences of insufficient sleep + state of social jetlag
decreases in cognitive and academic performance, safety, mental health, physical health.
True or false: The SCN clock cells act in a synchronised fashion?
True
