Human Nervous System Flashcards
Nervous system
Communication system needed by all organisms to sense changes in environment and control responses to these changes in order to survive
Nervous system functions
- Gathers information using senses
- Transmits info to brain
- Processes info
- Formulates responses to stimuli
- Sends info back through network of effector organs to execute response
Parts of nervous system
Brain
Nerves
Spinal cord
Central nervous system
Made up of brain & spinal cord
Parts of brain we’re exploring
Cerebrum
Cerebellum
Corpus callosum
Medulla oblangata
Spinal cord
Corpus callosum
Structure connecting left & right hemisphere of brain allowing communication between them
Medulla oblangata
Part of brain merging with spinal cord controlling involuntary reflexes
e.g) regulation of cardiovascular & breathing activity
Meninges
Membranes that protect brain
Skull
Rounded Kaye rof bone meant to protect brain from penetrating injuries
Interior skull surface danger
Many protuberances with ridges that can cause injury to temporal lube of brain during rapid acceleration
blood vessels of skull
Brain Requires rich blood supply & space between skull & cerebrum contain these.
Whag happens when blood vessels are ruptured in skull
Result in bleeding
Stroke
Broken blood vessel causing pressure in brain resulting in brain not recieveing oxygen & nutrients
Therefore dies
Pituary gland
Part of brain secreting endocrine hormones
Hypothalamus & importance
Control center (e.g, hunger, sleep, emotions)
Importance :
Regulates body temp, food intake, osmoregulation
Controls autonomic nervous system, sleep wake cycles, endocrine system
Cerebrum
Largest part of brain controlling:
voluntary actions
recieving & interpreting sensations
Higher mental /emotional activities
Visual cortex
sensory impulses travel from eyes via optic nerve into this part of cerebrum.
Damage results to blindness
Auditory areas
Side parts of cerebrum that used for hearing
Cognition
Front of cerebrum controlling higher mental activities & allowing one to feel emotions.
Damage to this causes mentak/personality changes.
Cerebellum
2nd largest part of brain that:
Maintains equilibrium
Coordinates half automatic movement of posture maintainance & walking
Adjusts muscle tone
Brainstem
Primitive part of brain controlling basic functions of life.
Divided into 3 parts : midbrain, pons,medulla oblangata
Afferent neuron
Neuron carrying impulses to CNS
Alzheimers disease
Progressive mental deterioration occurring in old age due to generalized degeneration of brain
Autonomic nervous system
Part of peripheral nervous system controlling involuntary actions
Cerebrospinal fluid
Watery fluid continuously produced & absorbed flowing in ventricles within brain and around surface of brain & spinal cord
Dementia
Term used for memory loss & loss of other intellectual abilities
Dendrite
Part of neuron that conducts impulses towards cell body
Efferent neuron
Neuron carrying impulses to CNS
Effectors
Muscles /glands responding to message from nervous system
Multiple sclerosis
Disorder of nervous system characterized by breakdown of myelin sheath of neurons
Nerve
Bundle of neurons
Neuron
One nerve cell
Neurotransmitter
Chemical released from a nerve cell which thereby transmits impulse from nerve cell to another nerve, muscle, organ or tissue
Peripheral nervous system
Part of nervous system made of cranial & spinal nerves
Receptors
Structures located in sense organs that convert a stimulus to impulse
Stimulus
Detectable change recieved by receptor & converted to an impulse
Synapse
Junction between 2 nerve cells consisting of minute gap across which impulses pass by diffusion of neurotransmitter
Spinal cord structure
Long Structure made of nervous tissue
Cannot repair itself
Protected by 33 Vertebrae with discs of cartilage between acting as shock absorbers
Three meninges
Spinal cord function
Pathway for impulses conducted from receptors to brain and brain to effectors
Processes reflex actions
Peripheral nervous system
Al nerves that are not part of CNS.
Transmits impulses from body to CNS to provide info from external & internal environment for response
Cranial vs spinal nerves
Cranial nerves supply nerves to head
Spinal nerves supply nerves to rest of body
PNS forms
Somatic nervous system
Autonomic nervous system
Somatic nervous system
Recieves info. from sensory organs and brain then stimulates skeletal muscles to contract or relax
Voluntary control
Autonomic nervous system
Control involuntary rxns to react to internal receptors and stimulates smooth muscles glands to respond.
Autonomic nervous system branches
Sympathetic branch that prepares body for energy expending
Paraymathetic branch that is active under restful conditions
These systems work antagonistically together
Double innervation
Two systems that have an opposite effect where one stimulates and the other inhibits e.g) each organ is innervated by sympathetic nerve and parasympathetic nerve
Structure & functioning of automatic nervous system
Made of Paraymathetic and sympathetic parts .
Every gland/organ is controlled by both parts
Controls involuntary events
Sympathetic nerves increase response
Parasympathetic nerves decrease response
Neurons
Specialised cells connecting brain and spinal cord to all other body parts
Nerves
Send and carry signals to and from all parts of body made of neurons
Parts of neurons
Dentrite
.Carry impulses to cell body
Axon
Carries impulse away from body
Cell body
Controls metabolism of cell
Myelin sheath
Fatty layer wrapped around Axon and dentrite acting as insulin and speeding up transmission of impulses
Types of neurons
Motor
Sensory
Inter/connector
Sensory neurons
Unipolar/bipolar afferent neurons carrying impulses to CNS
Inter neurons
Multipolar neurons recieving impulse from sense organs and carrying impulse towards motor neurons
Motor neurons
Multipolar efferent neurons carrying impulses away from CNS
Synapse
Point where impulse passes from terminal branch of Axon of one neuron to dendrite of next neuron
Synapse
Point where impulse passes from terminal branch of Axon of one neuron to dendrite of next neuron
Synaptic gap
Gap between 2 neurons
Chemical neurotransmitters
Transmit impulse from one neuron to next across synaptic gap like dopamine
Synapse significance
Ensures impulse travels in one direction
Enables unnecessary background stimuli to be filtered out
Can speed up, slow down or block nerve impulse
Channels impulses so rxns are integrated and become part of learning & remembering
Reflex rxn
Automatic response to stimulus
Reflex arc
Pathway where impulse is transmitted to bring about automatic response to stimulus during reflex action
How nervous impulse travels in reflex arc
Goes to spinal cord then impulse passes from spinal cord directly to an effector to give an immediate response
Significance of reflex action
Allows for quick response to prevent damage to body without thinking
5 basic elements of reflex arc
Receptor
Sensory neuron
Intergration center
Motor neuron
Effector
Alzheimers disease
Form of dementia caused by Disorder of nervous system leading to nerve cell death and tissue loss throughout brain causing it to shrink and affect nearly all it’s functions
Symptoms of alzheimers disease
Slow thinking
Behavioral changes
Confusion
Difficulty speaking, swallowing, walking, recognizing familiar ppl
Cure to alzheimers and multiple sclerosis
None
But stem cell research and therapeutic cloning hold to great potential for providing cure
Multiple sclerosis
can be managed by healthy lifestyle
Stem cell research & biologically engineered production of interferon slow down progress of disease
Multiple sclerosis
Progressive degenerative disorder of CNS resulting in damage if myelin sheath of nerve cells (demyelination) making it impossible for impulses to move across these areas of scattered patches of demyelination
Cause of Ms & symptoms
Auto immune disease
Affects
Movement, feeling, coordination, balance
Fatigue
Bladder
Pain
Concentration & memory loss
Mood swings
Vision, tingling & numbness
Receptors
Consist of special sensory cells that respond to specific stimulus
Homeostasis
Process to maintain balanced internal environment within body
