04. Important Information Flashcards
How big is the human brain?
About the size of a cantelope
What is the research specialty that studies the brain?
Neuroscience
Name the subfield that studies the relation between the brain and bahaviour
Behavioural neuroscience
The human brain is what percentage of body weight?
2%
How much of the metabolic rate of the human body is taken up by the brain?
20%
How many nerve cells (neurons) does the human brain have?
86 billion
How do neurons communicate with each other?
Through synapses
How many synapses does the human brain have?
100 trillion
List the parts of the central nervous system
Brain and spinal cord
What is the peripheral nervous system comprised of?
Nerves which extend from the central nervous system
What do nerves connect the central nervous system to?
the body’s sensory organs, muscles and glands
List the 3 basic parts of a neuron
- Cell body, 2. Dendrites, 3. Axon
What is the cell body
The widest part of the neuron, contains the nucleus and other basic machinery common to all bodily cells
What are dendrites
Thin tube-like extensions that function to receive input from the neuron
What is difference between dendrites in interneurons and motor neurons and those in sensory neurons?
Dendrites in motor neurons and interneurons branch out from the cell body and dendrites in sensory neurons branch out from one end of the axon rather than the cell body
What is an axon
Thin tubelike extention that carries messages to other neurons or muscle cells
How can neurons convey varying degrees of intensity in a message via (all-or-none action potentials)
By varying the rate of producing acton potentials
What influences the action potentials in motor and sensory neurons
Sensory- sensory stimuli acting on dendrites
Motor- other neurons acting on the axon at its junction with the cell body
How do action potentials move along an axon
Once an action potential occurs along one part of an axon, it depolarises the area just ahead of it, triggering another action potential there. And so, over and over, it moves along the axon.
List 2 determining factors for the speed at which an action potential moves
- the diameter of the axon (larger= faster)
- If there is a mylelin sheath (present=faster)
Which is the last area to be myelinated?
The frontal cortex
Who has more neurons in their brains adults or new borns?
new borns
What are three methods used to identify the functions of specific brain areas
- observing behavioural deficits (part of brain destroyed or temporarily inactivated)
- Observing behavioural effects (artificially stimulating part of the brain)
- recording changes to neural activity (person/ animal engaged in specific mental/ behavioural task)
How can TMS be used for the study of brain activity
The magnetic stimulation can be used to study the effect of temporary activation or inactivation of a specific brain area
How can EEC patterns be used
They can be used as an index to determine if a person is highly aroused, relaxed, or asleep and can identify various stages of sleep
How is the nervous system organised?
Heirarchically
What is the function of the sensory perceptual hierarchy?
Data processing
What is the direction of flow in the sensory perceptual hierarchy?
Bottom (sensory receptors) to top (perceptual centres of the brain)
What is the function of the motor-control hierarchy?
Control of movement
What is the direction of flow in the motor-control hierarchy?
top to bottom
Do nerves exist in pairs?
Yes
How many pairs of cranial and spinal nerves do humans have?
cranial= 12
spinal= 31
How can the nervous system control behaviour?
Through action potentials along motor neurons which send messages out to the muscles and glands
What are the two broad classes of structures which motor neurons act upon?
- Skeletal muscles (attached to bones)
- Visceral muscles (e.g. wall of heart/ stomach) and glands
Which neurons act on skeletal muscles, and which on visceral muscles and glands
skeletal= somatic portion peripheral motor system
visceral/glands= autonomic portion of per. motor system
What is the difference (in terms of activity) between somatic/ skeletal and autonomic neurons?
Skeletal= initiate activity
Autonomic= modify activity
Most visceral muscles and glands receive two sets of neurons from the autonomic system
sympathetic and parasympathetic
The spinal cord contains ascending and descending tracts, what do they do?
Ascending= somatosensory information from spinal nerves to brain
Descending= motor control commands down from the brain
How does the limbic system’s connection to the basal ganglia function?
The limbic system receives input from all the sensory organs. Its connection to the basal ganglia helps to translate emotions and drives into actions
Describe the cerebral cortex (divisions, and lobes)
Two divisions (hemispheres) right and left, each hemisphere has 4 lobes (from back to front)- occipital, temporal, parietal, and frontal
List the 3 categories of functional regions/ areas or the cerebral cortex
- primary motor area
- primary sensory area
- association areas
What is the portion of the cerebral cortex that has expanded the most in human beings compared to other animals?
prefrontal cortex
How do hormones influence behaviour?
- They affect the growth of peripheral bodily structures (muscles, bones) which influences behavioural capacity.
- They impact metabolic processes (influence amount of energy available).
- Act in the brain in a way that influences drives and moods.
Where is the pituitary located and what does it do?
It sits at the base of the brain and is sometimes called the master endocrine gland because it produces hormones that in turn stimulate the production of other hormones by other glands.
The hormone that has the most influence on male animal’s sex drive is?
Testosterone
What is the term used for the menstrual cycle in non-human mammals?
Estrous cycle (strongly controls sex drive in most mammals)
What is the most obvious distinciton between the two cortical hemispheres in human brains?
Left= language
Right= non-verbal, visuospatial analysis of information
How can neurons change over time?
They can change their size, shape, excitability, and patterns of connections in ways that help their possessor to adapt to life’s ever-changing circumstances
Name one factor that can change the structure of the brain
experience
Where is the main area shown to generate new neurons in the brain
hippocampus (associated with learning and memory, especially of spacial locations)
What is the change in the brain that has most clearly been linked to learning
strengthening of synaptic connections between already existing neurons
What is the evidence that LTP is actually involved in learning
Experiments that show that disturbing the brain’s normal capacity for LTP interferes with the animal’s ability to learn
