Biological Influences Flashcards
Neuron
a specialised cell transmitting nerve impulses; a nerve cell
Axon
a part of the nerve cell that transmits information from the cell body to other neurons or to cells in glands and muscles
Cell Body
the part of a cell that contains the nucleus; controls the maintenance and metabolic functions of the cell
Central Nervous System
the brain and spinal cord
Peripheral Nervous System
all neurons in the body except the CNS
Cortex
the outer layer of the forebrain; it has two halves or hemispheres
Hemispheres
two halves of the cerebral cortex that are separated by a deep groove
Lobes
areas of the brain that have different functions and are defined by grooves (fissures) in the cortex
Sensation
taking in information through our sense organs
Neurotransmitter
a chemical substance which is released at the end of a nerve fibre by the arrival of a nerve impulse and, by diffusing across the synapse or junction, to transfer the impulse to the next neuron
Synaptic transmission
chemical transmission of signals between neutrons combined with electrical transmissions of signals along neurons
Stimulant
a drug that excited the nervous system and arouses the body’s function
Depressant
a drug that slows the activity of the nervous system and slows bodily functions
Hormones
chemical messengers produced by endocrine glands
Psychoactive drugs
is a chemical substance that acts primarily upon the central nervous system where it alters brain function, resulting in temporary changes in perception, mood, consciousness and behaviour
Heredity
the passing on of physical or mental characteristics genetically from one generation to another
Gene
basic unit of heredity
Mitosis
the process whereby a cell duplicate its chromosome and divides into two identical cells
The human nervous system
- complex communication system: monitors and controls
- consists of PNS and CNS that work together consisting of billions of neutrons
- uses chemical/electrical means to send messengers
Role of nervous system
- receives sensory information
- processes information
- transmits messages around body
- reacts to stimulus
Central Nervous System (CNS)
- consists of brain and spinal cord
Spinal cord
- delicate cable of nerve fibres
- base of the brain to lower back
- connects the rest of the body to the PNS
Peripheral Nervous System (PNS)
- consists of all the nerves outside the CNS
- carries sensory information from body to CNS back to body
- carious out via spinal cord
Sympathetic Nervous System (fight/flight)
- emergency/arousal system
- during times of high emotion: stress/threat
- increases activity level of some body systems
- Adrenaline and noradrenaline (increase HR, BR, BP)
Parasympathetic Nervous System (rest/digest)
- reverses effect of the sympathetic nervous system
- functions return to normal
- keeps body in a state of wellbeing or homeostasis
Neurons
- brains is made of billions
- trillions of synapses that are connected between these cells
- connections enable messages to be transmitted from one neutron to another throughout the body
Dendrites
fine branches from cell bod the receive messages
Myelin Sheath
protects the axon and assists with transmission of nerve impulses
Somatic Nervous System
- monitors bodily functions
- receives sensory information from organs such as skin, ears, eyes
- carries messages from CNS to muscles
- helps understand what is going on in the environment
VOLUNTARY
Autonomic Nervous System
- neurons sending messages from the brain to smooth muscles - hear, lungs, blood vessels
AUTO(matic) - INVOLUNTARY
The forebrain
- upper most part of the brain and consists of the cerebrum and limbic system and thalamus and hypothalamus
- outer brain areas are involved in perception, learning, motor and conceptual activities
- centre brain area is involved in internal and bodily functions (e.g. body temp, reproduction, eating, sleeping, emotions)
- how we think, act, behave
Cerebrum (cerebral cortex)
- control motor and mental activity
- develops in early childhood
- divided into left/right hemispheres
- outer layer of brain
Cerebellum
- lies below the cerebrum
- responsible for motor control and balance
- nerve connections that go to most of the sense organs
- contributes to making movements coordinated and precise
- makes sure movements are smooth rather than jerky
- damage might walk as if you were drunk
Brainstem
- lowest part of brain
- connects the brain to the spinal cord
- MIDBRAIN, PONS, RETICULAR SYSTEM, MEDULLA OBLONGATA
- relays messages
- important in hearing/vision
- functions; breathing, sleep patterns, hunger, thirst, blood pressure, heart rhythms, body temperature
Spinal cord
- runs down from brain stem
- relays messages between brain and body
- organised into 32 segments with sensory and motor neurone attached - start of PNS
- 12 cranial nerves that leave the brainstem at the top of the spine
Neurons
- send messages to the brain: sensory
- send messages to the body: motor
Cranial nerves
- carry sensory input from the skin or motor output to the muscles of the head/face
- carry information for vision, hearing etc
Frontal lobe
- characterised by the primary motor area and broca’s area
- frontal lobe is associated with thinking, decision making, feeling and behaviour
- determines behavioural responses
- coordinated the function of other lobes
- higher mental ability and control of movement
damage: change in personality, reduced capacity for problem solving
Frontal lobe: primary motor cortex
- located at the back of the frontal love
- generates neural impulses that pass down to the spinal cord to plan and control movement
- does this by controlling the skeletal muscle
- the primary motor cortex in the left frontal lobe contains controls the right side of the body
Frontal lobe: Broca’s area
- used in production of speech
- usually found in the left frontal lobe
- damage to this area can result in language loss and is known as Broca’s aphasia
Parietal lobe
- sits behind frontal love, on top of the cortex
- responsible for bodily sensations (mainly touch)
- spacial awareness
- aspects of speech
- enables individuals to read, write and solve math
Parietal lobe: damage
- problems with math, reading, writing, loss of imagery, visualisation
- reduction in bodily feelings
Occipital lobe
- directly behind and below parietal lobe
- responsible for visual functions of the eyes
- consists of the primary visual cortex
- involved in visual perception and colour recognition
Occipital lobe: damage
- full blindness
- partial blindness
- word blindness
Temporal lobe
- base of cortex
- important in auditory perception, language and speech production and memory
- receives info from ears and interprets sounds
- contains: limbic system, amygdala, hippocampus, wernicks area
Damage: affects persons language ability
Temporal lobe: wernick’s area
- linked to brocas
- involved in speech production
- language comprehension is impaired, speech remains normal
- mimicking words and syllables
Dopamine
- learning, attention, pleasurable senstations
Serotonin
- sleep, mood
- less can be linked to depression
Noradrenaline
- helps the body to deal with danger or threats
Endorphins
- allow perceptions of pain
- release when experiencing a positive mood
The endocrine system
- hormones are released by endocrine glands throughout the body and travel through the blood stream
- hormonal responses are slower than nervous responses
- from the blood stream, the hormones communicate with the body by heading towards their target cell to bring about a particular change of effect to that cell
Adrenaline
ADRENIAL GLAND
- responsible for flight/flight
- increasing heart rate, blood pressure
- expands air passages or lungs
- enlarges pupils
- alters bodies metabolism
Thyroxin
THYROID GLAND
- development brain and NS
- effects bones, reproductive, digestive and cardiovascular systems, energy production, basal metabolic rate (BMR)
- controls mental altertness
Growth
PITUITARY GLAND
- growth
- development
- released during sleep
Testosterone
TESTES
- stimulates the male secondary sexual characteristics
Oestrogen
OVARIES
- stimulates the female secondary sexual characteristics
- repairs wall of uterus
- controls ovulation
Progesterone
OVARIES/PLACENTA
- prevents the wall of the uterus breaking down
Stimulants
- increase heart/breathing rates
- decrease appetite because blood sugar rises
- gives energy and confidence boosts
- people use stimulants to stay awake, lose weight, boost athletic performance
- after effects can include headaches, tiredness and irritability
- highly addictive
Hallucinogens
- mind-altering drugs
- change perceptions and can result in vivid images
- can be natural in origin (marijuana and mushrooms)
- some are synthetically produced (LSD)
Marijuana
- mild hallucinogen
- reduces inhibitions
- increases sensitivity to sounds, colours, tastes and smells
LSD
- ‘trip’ can range from one of euphoria to one of absolute terror and panic
- user’s mood and expectations can affect the ‘trip’
Ecstasy
- stimulant and mild hallucinogen
- creates heightened emotions and a feeling of connectedness with those around them
causes: dehydration, overheating, increased blood pressure, potential death (due to previous symptoms)
long term: deflated mood, memory loss, damage to immune system
Drugs affect on brain
Healthy: high dopamine levels - normal pleasure/interest
Drug abuser: low dopamine levels - lack of pleasure
Alcohol affect on brain
Forebrain: assaults motor coordination and decision making
Midbrain: lose control over emotions and increase chances of blackout
Brainstem: affects HR, body temp, appetite and consciousness
Benefits of physical activity
- numerous studies show that a moderate amount of exercise has benefits for out physical health, halving the risks of hear attacks and adding two years to life expectancy
studies - exercise
- studies in Canada has found that 1 in 4 Canadians who exercised regularly report feeling more energetic, less depressed and tired less often
Exercise and depression
- cheaper
- more effective that no intervention
- more acceptable to patients than antidepressants
Positive effects of exercise
- strengthens heart, increases blood flow, lowers blood pressure
- promotes perceived ability to cope with depression
- increases the production of mood boosting neurotransmitters
neurotransmitters and exercise
- chemical that affect the way messages are passed from one neuron to another
- carry a message from sending neuron across a synapse to a receptor site on a receiving neuron
- NORADRENALINE
- ENDORPHINS
- SEROTONIN
Hindbrain
- base of the brain near the back of the skull
- brainstem and cerebellum
- controls vital activities over which we have no conscious control
Midbrain
- sits on top of brainstem under cerebral hemispheres
- brains sensory switchboard
- receives messages from sense and sends them on to higher regions of the brain
EEG or electroencephalograph
- used to investigate whole brain rather than parts
- measures brain waves or electrical activity
CT or CAT
- type of x-ray that involves sending a series of narrow beams through the head
- scans through 180 degrees and takes measurements
- cross-sectional picture of brain is produced
- aid in detection of tumours, strokes and other injuries
MRI
- uses strong magnetic field, radio frequency pulses and computers to produce an image of the brain
- patient places in a tunnel surrounded by a large magnet that produces a magnetic field
- body emits a signal that can be measured
- 3D image
- enables detections of tumours and abnormalities
fMRI
- used to measure activity of the brain when neutrons are consuming oxygen
- measures brain function
- parts of brain are active, it contains more oxygen-rich blood
- higher levels of oxygen means higher levels of oxyhemoglobin which indicated higher activity
PET
- based on glucose consumption of the brain
- glucose containing a harmless radioactive tracer is injected or taken orally
- can show which areas of the brain are using more energy or consuming more glucose
- higher glucose levels reflect higher brain activity
- epilepsy, tumours and blood clots can be identified
