Biopsychology Flashcards
The two main functions of the nervous system
- To collect, process and respond to information in the environment
- To co-ordinate the working of different organs and cells in the body
The nervous system
Our primary communication system/a network of cells.
What is the central nervous system made up of?
The brain and the spinal cord.
What is the nervous system separated into?
The central nervous system (CNS) and the peripheral nervous system (PNS)
Parts of the peripheral nervous system
Somatic nervous system and autonomic nervous system
Parts of the somatic nervous system
Sensory neurons and motor neurons
Parts of the autonomic nervous system
Sympathetic division and parasympathetic division
Brain
- Centre of consciousness
- Made up of billions of interconnected neurons
- Bilateral (two-sided)
- Separated into distinct lobes each associated with certain types of functions
- All areas of the brain interact with one another
Spinal cord
- An extension of the brain
- Responsible for reflex actions
- Routes messages to and from the brain
- Cord is organised into 30 segments which correspond to the vertebrae
- Each segment is connected to a specific part of the body through the PNS.
Peripheral nervous system (PNS)
Connects the CNS to the rest of the body.
Somatic nervous system
Controls muscle movement and receives information from sensory receptors. Associated with conscious and voluntary behaviours. Involved in the relay of sensory and motor information to and from the CNS.
Autonomic nervous system
Governs vital functions such as breathing, heart, digestion, sexual arousal and stress response. It is involuntary.
Sensory neurons
- Carry information from sensory receptors (vision,taste,touch etc.) to the CNS
- They convert information from these sensory receptors into neural impulses
Motor neurons
- Takes information from the CNS to muscles and glands in the body.
- Form synapses with muscles and control their contractions
- Release neurotransmitters that bind to receptors on the muscle and trigger a response, leading to muscle movement
Sympathetic division
- Ready for action/fight or flight response
- Involved in preparing the body for stress-related activities e.g. increasing heart rate and blood pressure
- Slows down body responses less important in emergencies such as digestion
- Responds to a perceived threat
Parasympathetic division
Sometimes referred to as rest and digest. Restores natural order in the body and returning it back to routine.
Homeostasis
A state of equilibrium in which biological conditions are maintained at optimal levels. The sympathetic and parasympathetic have complementary functions and work in tandem to maintain the body’s homeostasis.
Reflexes
Reactions to stimuli that are rapid and automatic as sensory input is immediately acted upon by the spinal cord without input from the brain.
Neurons
The main building blocks of the nervous system. They have a structure which is specialised to their function.
The structure of neurons
- Nucleus located in the soma (cell body)
- The soma has branching extensions known as dendrites
- Dendrites act as input sites where signals are received from other neurons
Axon
A major extension from the soma
Terminal buttons
Contain synaptic vesicles that house neurotransmitters and release them into the synapse.
The action potential from an electrical impulse moves rapidly down the axon to the terminal buttons.
Synapse
A very small place between two neurons. An important site where communication between neurons happens.
Synaptic cleft
The space between two neurons.
Synaptic knob
The bulb shaped end of a neuron where it meets another neuron.
Synaptic vesicles
In the synaptic knob and are where neurotransmitters are stored before release into the synaptic cleft.
Neurotransmitter
A chemical messenger that carries information from one neuron to another.
Neurotransmitters can be divided into those that perform an excitatory function and those that perform an inhibitory function.
Receptors
Proteins on the cell surface where neurotransmitters attach.
Specific neurotransmitters fit specific receptors (lock and key relationship)
Relay neurons
Allow sensory and motor neurons to communicate with each other. They lie wholly within the spinal cord.
Inhibitory neurotransmitters
The nervous system’s “off switches” and are generally responsible for calming the mind and body including sleep and filtering out unnecessary excitatory signals.
They decrease the likelihood of a new action potential forming in the postsynaptic cell
Excitatory neurotransmitters
The nervous system’s “on switches”. They cause excitation of the post synaptic neuron by increasing its positive charge and making it more likely to fire (increasing the likelihood of a new action potential forming in the postsynaptic cell)
Dopamine
- Can be both an excitatory or inhibitory neurotransmitter depending on the receptor it binds to
- Associated with rewards as the brain releases it in response to pleasure
- Responsible for movement co-ordination and is implicated in Parkinson’s disease
- Excess dopamine in certain regions of the brain is associated with positive symptoms of schizophrenia
Serotonin
- Inhibitory neurotransmitter
- Regulates sleep, mood and appetite
- SSRIs relieve the symptoms of depression by increasing levels of serotonin in the brain
Dendrites in sensory neurons are…
Long
Axons in sensory neurons are…
Short
Dendrites in relay neurons are…
Short
Axons in relay neurons are…
Short
Dendrites in motor neurons are…
Short
Axons in motor neurons are…
Long
Myelin sheath
- An insulating layer around axons
- Made of protein and fatty substances
- Allows electrical impulses to transmit quickly and efficiently along the nerve cells
- Sensory neurons and relay neurons have a myelin sheath
Nodes of Ranvier
Gaps in the myelin sheath coating on the axon.
The endocrine system
Made up of a series of glands that produce hormones
Hormones
- Chemical messengers that must bind to a receptor in order to send their signal
- Secreted into the bloodstream and travel around the body
- Slower to take effect than neurotransmitters
Pituitary gland
- Descends from the hypothalamus at the base of the brain
- “Master glad” - its messenger hormones control all the other glands in the endocrine system
- Secretes growth hormone, endorphins for pain relief and hormones that regulate fluid levels in the body
The thyroid gland
- Located in the neck
- Releases hormones that regulate growth, metabolism and appetite
Examples of thyroid disorders
Hyperthyroidism
Grave’s disease
What causes hyperthyroidism or Grave’s disease/What are the symptoms
- When the thyroid secretes too much of the hormone thyroxine
- Symptoms include weight loss and agitation
Adrenal glands
- Located on top of the kidneys
- Secrete hormones involved in the stress response such as adrenaline and noradrenaline
The pancreas
Secretes hormones that regulate blood sugar (insulin and glucagon)
Insulin
Lowers blood sugar levels
Glucagon
Raises blood sugar levels
Gonads
- Secrete sexual hormones
- Mediate sexual motivation and sexual behaviour
Ovaries
- The female gonads
- Secrete oestrogen and progesterone
Testes
- The male gonads
- Secrete androgens such as testosterone