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Flashcards in Physio and Psychopharm Deck (124)
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1

Neuron (Nerve Cell)

Neuron (Nerve Cell)  is a specalized cell that conducts info. in the nervous system & neurons can vary in size & shape.

Neurons consist of 3 parts:

  1. Dendrites (Branch Like): Recieve info from other cells & conduct it toward the cell body.
  2. Cell Body (SOMA): Contains several structures including:
    • Nucleus
    • Mitochondria: Site where the cell perf. metabolic acitivites.
    • Ribosomes: Site where cell synthesizes new protien molecules.
    • Golgi Complex: System of membrane that prep neurotransmitters & other sub for secretion.
  3. Axon: Then transmit info. from the cell body to other cells by releasing neurotransmitters
  4. Synaptic Cleft: Goes into this area which is the gap btwn the axon terminal of the presynaptic cell & receptors on the dendrite of the post-synaptic cell.

Most neurons have a single axon that divides into numerous branches & many axons are connected by a Myelin Sheath: A fatty substance that acts as an insulator & speeds up the conduction of nerve impulses.

2

Neuron (Action Potential)

The neuron (nerve cell) is a specialized cell that is directly involved in mental processes & behavior. Messages w/in a neuron are transmitted from a neuron's dendrites to the end of its axon through an electrical process called conduction.

With sufficient stimulation from other cells, a cell becomes:

  • Depolarized (the interior of the cell becomes less negative), which triggers an action potential- i.e. an electrical impulse that travels quickly through the cell.

3

Neuron (All-or-None Principle)

Predicts that an action potential will always be of the same magnitude regardless of the amount of stimulation received by a neuron as long as the minimal level of stimulation (the threshold) has been reached.

4

Neurotransmitters

Chemical substances that are released from axon terminals, diffuse across synapses, & excite or inhibits receptor sites on postsynaptic nerve cells.

Neurotransmitters Include:

  • Acetylcholine (ACh)
  • Dopamine (Catecholamine)
  • Norepinepherine (Catecholamine)
  • Epinepherine (Catecholamine)
  • Serotonin (5-HT)
  • Gamma-Amino Butyric Acid (GABA)
  • Glutamate
  • Endorphins

5

Acetylcholine

Neurotransmitter found in the somatic nervous system.

Released into neuromuscular junction that mediates neuromuscular transmission, & controls the acions of the skeletal muscles & in automatic nervous system, it controls the internal organs & glands. contract

Involved in voluntary motor movement, parasympathetic arousal, sleep, important role in learning & memory

  • Too much assoc. w/Depression
  • Too little (in Hippocampus) assoc w/Dementia (e.g. memory loss in Alzheimers disease)

    • Declines in memory assoc. w/normal aging & Alzheimer's disease are related to deterioration of neurons that secrete ACh, especially in the hippocampus & areas of the drain that communicate directly w/the hippocampus.
       

6

Dopamine

Neurotransmitter classified as a catecholamine (Norepinepherine, epinepherine) Fx's include:

  • Involved in mood, motivation/emotional Fx's & voluntary movement
  • Personality, mood, memory, sleep, attention & learning
  • Too little:
    • Parkinson's Disease: A degeneration of dopamine producing cells in the substantia nigra & basal ganglia (Muscle rigidity & tremors) &
    • Forms of Depression
  • Too Much linked to:
    • Schizophrenia: According to Dopamine Hypothesis - Is due to oversensitivity to or higher-than-normal levels of dopamine in certain regions of the brain. (Rx reduces dopamine, decrease + Sx's; Antipsychotics)
    • Tourtte's Disorder 

​Cocaine, Amphetamines & other stimulant drugs elevate mood my increasing levels of dopamine in areas of the midbrain & limbic system that have been ID as part of the brains reward system.

Alcohol increases dopamine levels & causes the pleasurable feelings related to alcohol use leading to reinforcing effects of alcohol additction.

7

Norepinepherine

Neurotransmitter assoc. with:

  • Mood, attention/alertness, dreams, learning, autonimic Fx, & eating
  • Too little assoc. w/Depression (Catecholamine Hypothesis)
  • Low levels also asoc. w/Bulimia & Eating D/O's

8

Epinephrine

Neurotransmitter involved in energy & glucose metabolism.

  • Too little assoc. w/Depression

9

Serotonin (5-HT)

Neurotransmitter that ordinarily inhibits behavior & is involved in:

  • Meditates arousal/mood regulation, appetite/hunger, thirst, sexual behavior, impulsive & aggressive behaviors, sleep, memory, body temperature, & pain
  • Too little assoc. with:
    • Affective Disorders (Dep.),
    • Mania
    • Anxiety D/O's (OCD)
    • Bulimia (Antidepressant Rx that increases serotonin levels have been found useful to control binge & purge behaviors)
  • Too much assoc. with:
    • Schizophrenia
    • Anorexia: Assoc. w/an excess of serotonin which causes nervousness & anxiety. Food restriction helps lower serotonin levels which reduce thses unplesant feelings.
      • Rx that increases serotonin are not useful for these indiv. but once they have reached normal weight Rx may help prevent weight loss.

Evidence that low levels of serotonin are involved in cravings for alcohol in abusers.

10

Gamma Amino Butyric Acid (GABA)

Neurotransmitter that is the most common inhibitory neurotransmitter & inhibits:

  • Excitation, anxiety, sleep, & seizures.
  • Abnormal levels of GABA in the motor region are associated w/Huntington's Disease.
  • Abnormal levels have also been assoc. w/Parkinson's Disease, Epilepsy & Sleep D/O's
  • Too little assoc. w/Anxiety & Anxiety D/O's. Some antianxiety Rx (Benzo's) increase GABA at receptor sites & reduce anxiety & enhance sleep.
  • Affected by CNS Depressants

11

Glutamate

A major excitory neurotransmitter that helps messages pass from one neuron to the next more effectively.

Plays a role in:

  • Learning & memory 
  • Long-term potentiation (LTP): Brain mechanism believed to be responsible for the formation of long-term memories.
  • Excessive levels can produce Excitotoxicity - which damages or destroys nerve cells & have been linked to stroke related brain damage, TBI, Huntington Disease & Alzhiemers Disease.
  • Alcohol alters Glutamate levels in the brain & are related to memory impairment & alcohol related black outs; responsible for the harmful effects alcohol has on memory.

12

Endorphins

(Endogenous Morphines) Inhibitory neuromodulator that lowers the sensitivity of postsynaptic neurons & neurotransmitters.

Have analgesic properties & involved in:

  • Pain Relief: Prevents release of substance P, involved in transmission of pain impulses.
  • Feelings of pleasure & contentedness, emotions, sexual behaviors, memory & learning.

13

Central Nervous System (CNS)

Consists of the:

  • Brain: Recieves & processes sensory info., initiates responses, stores memories, generates thoughts & emotions.
  • Spinal Cord: Sends signals to & from brain; controls reflex activity

14

Spinal Cord (Quadriplegia & Paraplegia)

The spinal cord carries info. btwn:

  • The brain & the peripheral nervous system,
  • Coordinates activities of the left & right side of the body, and
  • Controls simple reflexes that do not involve the brain.

Consists of 31 segments, which are divided into 5 groups. Each nerve consists of bundles of axons.

From the top of the spinal cord to the bottom, these are:

  1. Cervical
  2. Thoracic
  3. Lumbar
  4. Sacral
  5. Coccygeal.

Damage at different levels causes different types of paralysis:

  • Quadriplegia: Occurs at the cervical level (loss of sensory & voluntary motor Fx in the arms & legs).
  • Paraplegia: Occurs at the thoracic level (loss of functioning in the legs; below T1)

15

Brain

16

Cerebral Ventricles/Hydrocephalus

The ventricles are the 4 cavities of the brain that contain cerebrospinal fluid.

  • Hydrocephalus: Blockage of the ventricles & a resulting build-up of fluid. 

17

Hydrocephalus

The abnormal accumulation of cerebrospinal fluid in the ventricles (aka Water head), which results in increased intracranial pressure & can lead to brain damage.

18

Peripheral Nervous System (PNS)

Made up of nerves (Bundles of axons) that relay messages btwn  the CNS & body's sensory organs, muscles & gland.

Peripheral Nervous System (PNS):

  1. Motor Neurons: CNS to muscles & glands
    • Somatic Nervous System (SNS): Controls Voluntary movements.
    • Automatic Nervous Systerm (ANS): Controls involuntary responses.
      • Sympathetic: "Fight or Flight"
      • Parasympathetic: Resting
  2. Sensory Neurons: Sensory organs to CNS

19

Somatic Nervous System (SNS)

Consists of sensory nerves that carry information from the body's skeletal muscles & sense receptors to the CNS & motor nerves that carry information from the CNS to the skeletal muscles.

  • Governs activities that are ordinarily considered voluntary.

20

Autonomic Nervous System (ANS)

(Sympathetic & Parasympathetic Branch)

ANS controls the glands & muscles of the internal organs & regulates bodily processes that we ordinarily don't consciously control such as digestion, respiration & HR.

Part of PNS & controls involuntary responses. It consists of 2 parts:

  1. Sympathetic Branch: Active during states of activity & energy output. Involved in the mediation of Flight or Fight (emergency) reactions. Activation of the sympathetic branch produces:
  • increased heart rate,
  • pupil dilation,
  • increased blood sugar, and
  • inhibition of the digestive processes
  1. Parasympathetic Branch:  Active during states of relaxation & energy conservation. Involved in the conservation of energy & relaxation (Para = Parachute come down/relax). Activation is associated with:
    • slowing of heart rate,
    • lowered blood pressure,
    • contraction of pupils,
    • reduction of sweat gland output, and
    • increased activity of the digestive system.
    • Hypnosis & meditation 

21

The 5 Stages of Brain Development (CNS)

Developmemnt of the Brain involves 5 Stage:

  1. Proliferation: Production of cells inside neural tube when embryo is 2.5 weeks.
  2. Migration: Each cell moves (migrates) to it's ultimate destination in the nervous system.
  3. Differentiation: (Grow axons & dendrites) Cells devel. the unique charachteristics of nerve cells.
  4. Myelination: The axons of some cells become surrounded (insulated) by glial cells.
  5. Synaptogenesis: Formation of synapses & depends on certain areas of brain, but most occur post natally. Appears to be influenced by both endogenous (genetic) & Exogenous (exp.) factors.

22

Neuroimaging Techniques

Make it possible to study both the structure & function of the living brain.

Structural Techniques:

  • Computed tomography (CT):
  • Magnetic resonance imaging (MRI): uses magnetic fields & radio waves to produce high quality 2/3D images of brain structures.

Functional Techniques: Provide info. on the functional activities of the brain.

  • Positron-emission tomography (PET),
  • Single proton emission computed tomography (SPECT)
  • Functional magnetic resonance imaging (fMRI): Measure brain activity, by detecting changes in blood oxygenation & flow in response to neural activity.

23

3 Divisions of the Brain (Structures)

Structure of the Brain categorized into 3 divisions:

  1. Hindbrain: From an evolutionary perspective, the hindbrain is the oldest part of our brain & is located deep w/in our head & on top of our spinal cord. This is the 1st & most basic brain it controls most of our most basic Fx's. There are 3 structures of the hindbrain:
  • Medulla Oblongata: Helps control our heart rate, blood pressure & breathing.  Located above the spinal cord.
  • Pons: Located just above the medulla & it helps coordinate the hindbrain w/the midbrain & forebrain; also involved in facial expressions.
  • Cerebellum: Located at the bottom rear of brain & looks like a little version of our whole brain (like mini me). Helps coordinate balance & fine muscle movements.  
  1. Midbrain: Located in the middle of ther brain, the midbrain does a lot, but primary Fx's are to coordinate sensory info. w/simple movements. Any sensory inputs, all 5 senses. There are 2 structures:
    • Substantia Nigra: Involved in motor activity & plays a role in the brains reward system. Reticular Formation: Control respiration, coughing, posture, locomotin, vomiting & REM sleep. 
    • Reticular Activating System (RAS): Controls wakefulness, arousal & consciousness.
  1. Forebrain: The most important part of the brain & contains the newest structures in the brain. There are 3 structures:
    • ​​​​Thalamus: The operator/switchboard of brain. Any sensory info. that comes into the body (sight, hearing, touch & taste) go thru the Thalamus 1st & sends the info. to the right parts of the brain to get processed (except for smell).
    • Hypothalamus: Size of a pea & the most important structure in the brain. Controls thirst, hunger, body temperature, sexual arousal & the endocrine system.
      • ​Suprachiasmatic Nucleus (SCN)
    • Limbic System: aka the emotional control center of the brain bc it contains structures that control raw emotions. It is made up of 3 structures:
      • Hippocampus:  Involved in memory processing (not stored here), but it does helps put memories in the right parts of brain.  Ex: Think of a librarian that does not store the info. of all the books in the library in her head, but can tell you where to find that info.
      • Amygdala:  Controls some memory processing, but for the most part handles basic emotions like anger & jealousy.
      • Septum

24

Hindbrain

Hindbrain: From an evolutionary perspective, the hindbrain is the oldest part of the brain & is located deep w/in the head & on top of the spinal cord. This is the 1st & most basic brain it controls most of the most basic Fx's. There are 3 structures of the hindbrain:

  1. Medulla Oblongata: Helps regulate automatic responses & helps control our heart rate, blood pressure & breathing.  Located above the spinal cord.
    • Damage can be fatal (Ex: SIDS)
  2. Pons: Located just above the medulla & it helps coordinate the hindbrain w/the midbrain & forebrain; also involved in facial expressions.
  3. Cerebellum: Located at the bottom rear of brain & looks like a little version of our whole brain (like mini me). Helps coordinate voluntary motor movements & is responsible for balance & posture & motor skills.
    • Abnormalities have been linked to Autism, Schizophrenia &ADHD. 

25

Medulla

Hindbrain: There are 3 structures of the hindbrain:

  1. Medulla Oblongata: Helps control flow of info. btwn the spinal cord & brain & regulates a number of vital Fx's such as heart rate, blood pressure & regulate breathing. Located above the spinal cord. (Reflexes/Unconscious)
  2. Pons 
  3. Cerebellum






     

26

Pons

Hindbrain: There are 3 structures of the hindbrain:

  1. Medulla Oblongata
  2. Pons: Located just above the medulla & it helps coordinate the hindbrain w/the midbrain & forebrain. Plays a role in integration of movement in right & left side of body, sleep & facial expressions.
  3. Cerebellum

     













 

27

Cerebellum and Ataxia

Hindbrain: There are 3 structures of the hindbrain:

  1. Medulla Oblongata
  2. Pons
  3. Cerebellum: A large structure on the dorsal aspect of the hindbrain.
    • Located at the bottom rear of brain & looks like a little version of our whole brain (like mini me). 
    • It is involved in the extrapyramidal control of motor activities (e.g., timing & coordination of movements, balance, posture).
    • STM, following rules & carry out plans

Damage can result in:

  • Ataxia: Which is characterized by slurred speech, severe tremors, & a loss of balance

28

Midbrain

Midbrain: Located in the middle of ther brain, the midbrain does a lot, but primary Fx's are to coordinate sensory info. w/simple movements. Any sensory inputs, all 5 senses. There are 2 structures:

  1. Substantia Nigra: Involved in motor activity & plays a role in the brains reward system. Reticular Formation: Control respiration, coughing, posture, locomotin, vomiting & REM sleep. 
  2. Reticular Activating System (RAS): Controls wakefulness, arousal & consciousness.

29

Reticular Activating System

Midbrain: There are 2 structures:

  1. Substantia Nigra
  2. Reticular Activating System (RAS): A network of nerve fibers involved in wakefulness, arousal, and consciousness.​​
    • ​​Damage = Disrupts sleep-wake cycles & can produce permanent coma like state of sleep.
    • Reticular Formation: Plays a role in arousal & consciousness & includes the:
      • Ascending Reticular Activating System (ARAS): Which is involved in selective attention & arousal.
      • Ex: A mother being awakened in the middle of the night by a babies cry but not other background noises.

30

Forebrain

Forebrain: The most important part of the brain & contains the newest structures in the brain. There are 3 structures:

  1. ​​​​Thalamus: The operator/switchboard of brain. Any sensory info. that comes into the body (sight, hearing, touch & taste) go thru the Thalamus 1st & sends the info. to the right parts of the brain to get processed (except for smell).
  2. Hypothalamus: Size of a pea & the most important structure in the brain. Controls thirst, hunger, body temperature, sexual arousal & the endocrine system.
    • Suprachiasmatic Nucleus (SCN)​
  3. Basal Ganglia: Involved in control of voluntary movement.
  4. Limbic System: aka the emotional control center of the brain bc it contains structures that control raw emotions. It is made up of 3 structures:
    • Hippocampus:  Involved in memory processing (not stored here), but it does helps put memories in the right parts of brain.  Ex: Think of a librarian that does not store the info. of all the books in the library in her head, but can tell you where to find that info.
    • Amygdala: Controls some memory processing, but for the most part handles basic emotions like anger & jealousy.
    • Septum