Physiological Flashcards
At resting state, what is the charge inside and outside the cell?
Inside the cell is negatively charged and outside is more positively charged (polarization)
What happens in a neuron when there is sufficient stimulation?
The cell depolarizers- sodium channels open allowing positively charged sodium ions to enter therefore making inside the cell to be more positively charged.
Depolarization leads to what?
Action potential
What happens after depolarization?
Repolarization-sodium channels close and potassium ones open therefore allowing positively charged potassium ions to leave making inside the cell more negatively charged than the outside of the cell
What principle does action potential work on?
All or none
What receptors does acetylcholine act on?
Muscarinic and nicotinic
What is acetylcholine responsible for?
Controls actions of the skeletal muscles (causes muscles contract) in the somatic nervous system.
Controls internal organs and glands in the autonomic nervous system.
In the CNS, it plays important role in learning and memory, as well as in REM sleep, regulation of sleep wake cycle.
Degeneration of ACh in the CNS can lead to what?
Memory deficits like that in Alzheimer’s disease
Degeneration of ACh in the peripheral nervous system can lead to what?
Profound weakness of skeletal muscles (myasthenia gravis is autoimmune disorder that attacks ACh at neuromuscular junctions)
What type of inhibitors are used to slow down memory decline with Alzheimer’s disease?
Cholinesterase (prevents breakdown of ACh) like tacrine (Cognex) donepezil (Aricept) galantamine (Reminyl) rivastigmine (Exelon)
What functions is dopamine involved in?
Mood, motivation, and voluntary movement. Also, personality and sleep.
What issues has dopamine been linked to?
Prominent motor symptoms like Tourette’s disorder and Parkinson’s. Also, it plays a key role in schizophrenia (dopamine hypothesis-disorder due to elevated dopamine levels or over sensitivity of dopamine receptors)
What is dopamine classified as?
Catecholamine
How does dopamine contribute to Tourette’s?
Over sensitivity to or excessive dopamine in the caudate nucleus
How does dopamine contribute to Parkinson’s?
Degeneration of dopamine receptors in the substantia nigra.
How does dopamine reinforce actions of stimulant drugs like opiates, alcohol or nicotine?
Cocaine drugs block the reuptake of dopamine and nicotine stimulates its release.
What is norepinephrine classified as?
Catecholamine
What is norepinephrine responsible for?
Mood, attention, dreaming, learning, and certain autonomic functions.
What is the Catecholamine hypothesis?
Predicts that some forms of depression are due to lower than normal levels of norepinephrine.
What type of effect does serotonin have?
Inhibitory
What functions does serotonin mediate?
Temperature, hunger, thirst, sexual behavior, aggression, arousal and sleep.
Elevated levels of serotonin is linked to what?
Schizophrenia, autistic disorder, and food restriction in anorexia nervous.
Low levels of serotonin is linked to what?
Aggression, depression, suicide, bulimia nervous, OCD, and PTSD
Does serotonin play a role in social phobia?
Yes
What type of effect does GABA have?
Inhibitory
What functions does GABA play a role in?
Eating, seizures, anxiety disorders, motor control, vision, and sleep.
What are low levels of GABA linked to?
Anxiety disorders - benzodiazepines reduce anxiety by enhancing the effects of GABA.
Abnormal levels of GABA is linked to what?
Huntington’s disease, Parkinson’s disease, epilepsy, and sleep disorders.
What type of effect does glutamate has?
Excitatory
What functions does glutamate play a role in?
Learning and memory
What important role does it play in memory?
Believed to play a role in long term potentiation - mechanism responsible for the formation of long term memories.
What can excessive levels of glutamate cause?
Excitotoxicity - lead to seizures that may contribute to stroke related brain changes
What are endorphins?
Endogenous morphines
What effect does endorphins have?
Inhibitory neuromodulators - lower sensitivity of post synaptic neurons to neurotransmitters
Analgesic properties- believe to prevent the release of substance P (involved in pain transmission)
What are the two main sections the nervous system divided into?
Peripheral and central nervous system
The CNS is subdivided into?
The brain and the spinal cord
What are the spinal nerve groups?
Cervical, thoracic, lumbar, sacral, and coccygeal
What does the peripheral nervous system do?
Relays messages between CNS and the body’s sensory organs, muscles, and glands.
The peripheral nervous system is divided into?
Somatic and autonomic
What is the somatic nervous system?
Governs activities that are generally considered voluntary. Carries signals from skeletal muscles and senses to the CNS and from the CNS to the skeletal muscles
What is the autonomic nervous system?
Mainly related to involuntary activities. Controls the glands and muscles of the internal organs.
The autonomic nervous system is divided into?
Parasympathetic and sympathetic
What is the parasympathetic nervous system?
Involved in the conservation of energy and is also active during digestion and rest.
What is the sympathetic nervous system?
Involved in the expenditure of energy; associated with arousal
Eg. dilation of pupils, sweating, ready body in fight or flight.