biological influences section - study :) Flashcards
Define the Central Nervous System
Consists of the brain and the spinal cord and is responsible for how we think, feel and perceive the world around us. It also enables us to make decisions, solve problems, have emotions etc.
Define the brain
Receives, integrates and processes information from the rest of the body, and generates a response to it
(RIP)
Define the spinal cord
Connects the brain to the rest of the body via its connection to the peripheral nervous system
Define the hindbrain
location - base of the brain at the back of the skull.
Consists of - the pons, medulla and cerebellum
Function - controls our basic survival functions (heart rate, breathing), co-ordinating voluntary movement and reflex actions (coughing, swallowing, vomiting)
Define the midbrain
Location - between the hindbrain and forebrain
Consists of - reticular formation
Function - keeps us alert, awake and vigilant (posture, movement, consciousness, sleep-wake cycle)
Define the forebrain
Location - top of the brain, above the midbrain
Consists of - hypothalamus, thalamus, cerebrum
Function - controls higher brain functions and processes (emotions, sensations, perceptions, reasoning)
Describe the types of matter in the spinal cord
Grey matter = made up of cell bodies, their axons and their dendrites
- centre of the spinal cord
White matter = columns of myelin coated axons (known as tracts)
- run of the outer layers of the spinal cord
What are the two types of tracts in white matter
ascending tracts and descending tracts
- involved in the transmission of information up and down the spine (highway)
sensory/afferent neurons - transmit information towards the CNS
motor/efferent neurons - transmit information away from the CNS
(SAME)
Describe the spinal cord’s process
the axon columns (tracts) are bundled together into spinal nerves that branch off between gaps in the vertebrate, going into the arms, legs and torso.
these spinal nerves carry the messages to and from the spinal cord, connecting it to the brain and the PNS.
Sensory neurons - enter the dorsal (back) side of the 31 spinal cord segments (the top)
Motor neurons - exit the ventral (abdominal) side of the 31 segments (the bottom)
Define the Peripheral Nervous System
All of the nerves outside of the CNS (brain and spinal cord), including the spinal nerves (connected to muscles, organs and glands) and cranial nerves (connected to the lobes of the brain)
Main function:
- transmit sensory information from the body’s internal and external environments to the CNS,
- transmit motor commands from the CNS to the rest of the body
Define the somatic nervous system
a subdivision of the peripheral nervous system, function - senses external stimuli (light, sound, touch) and controls a voluntary response, process - sensory neurons receive sensory info from receptor cells (skin, joints, eyes) and transmits the info to the CNS (experience heat, etc.) Motor neurons receive commands from the CNS, which is transmitted to the appropriate skeletal muscle to enable voluntary movement
(voluntary, involves the brain)
Define the autonomic nervous system
a subdivision of the PNS
function - controls the activity levels of our internal organs / glands, which are responsible for survival
process - transmits motor commands from the brain to the ‘smooth muscles’ (heart, pupils) to regulate activity levels (pump more adrenaline, etc.)
(involuntary, independent from the brain)
- has 2 subdivisions: sympathetic, parasympathetic
Define the sympathetic nervous system
A subdivision of the autonomic nervous system which causes an arousing effect. function - dominates when we experience heightened emotions, or during vigorous physical activity (also when flight/fight response is activated) e.g. jump scare in horror movie
(automatic - no voluntary control)
Define the parasympathetic nervous system
A subdivision of the autonomic NS, which causes a calming effect.
Function - maintains a level of homeostasis (keeps internal systems at a balanced, healthy state by maintaining vital functions - e.g. heart rate, blood pressure)
(automatic - no voluntary control)
Outline what the Sympathetic NS does for a scenario
= it uses the body’s internal resources to provide extra energy that is required for increased physical activity or to deal with intense emotions (e.g. fear) or stressful/threatening situations
- Sensory / afferent neurons receive the sensory information from receptor cells of the perceived threat (hearing footsteps behind you, seeing the clown), which is transmitted to the CNS via the spinal cord.
- The brain receives, integrates and processes the information, and the sympathetic nervous system is automatically activated to prepare our body for emergency action (flight or fight response)
- The brain transmits motor / efferent neurons to the PNS to carry out the following actions: …
Outline symptoms of a sympathetic response
adrenaline levels increase
- increased heart rate = increased response time
increased heart rate and blood pressure
= carry more oxygen to the body
increased respiration rate
= quicker reaction time
Increased muscle tension
= quicker reaction time
Dilated pupils
- more visual information
Inhibited digestion and saliva
Relaxed bladder
Outline symptoms of a parasympathetic response
Decreased hormone activity
Decreased heart rate to normal function
Respiration rate returns to normal
Relaxed muscles
Constricts pupils
Stimulates digestion and salivation
Contracts bladder
Define stress
= A state of intense arousal, caused by our internal organs operating at abnormally high levels – when the sympathetic nervous system is still active long after the perceived threat is gone
- Being stressed for a long time can be dangerous, as we can develop physiological / psychological disorders – can lead to a breakdown
Define spinal reflex arc
An automatic response to ‘emergency’ sensory stimuli, through interneurons instead of the brain.
Describe the process of the spinal reflex arc
- Pain receptors are stimulated (e.g. in skin, when touching an iron)
- This triggers an impulse (action potential) which passes along the sensory neuron, to the dorsal root of the spinal cord
- Instead of going to the brain, the impulse passes through an interneuron located in the spinal cord
- The interneuron sends a motor command (exiting through the ventral root of the spinal cord), causing muscles to contract from the painful stimuli
- The brain then receives and processes the impulse, after the reaction has happened
Define neural transmission
the function of a neuron to transmit messages within the nervous system.
Define neuron
a type of cell specialised to receive, transmit and process information.