Biological Psychology Flashcards
(81 cards)
1
Q
From Axon to Synapse: 1) Synthesis & Storage
A
- Neurotransmitters (chemical messengers) are synthesised by Golgi Apparatus
- Neurotransmitters are stored in spherical packets called Synaptic Vesicles
- Synaptic Vesicles are passed down microtubules to the Pre-Synaptic Button
2
Q
From Axon to Synapse: 2) Receiving the Action Potential
A
- Synaptic vesicles float around waiting for an action potential to arrive
- The Action Potential (electrical) is received by the pre-synaptic membrane causing depolarisation (membrane becomes more positive)
3
Q
From Axon to Synapse: 3) The Effects of Depolarisation
A
- Depolarisation causes vesicles to dock on pre-synaptic membrane
- Depolarisation causes Calcium channels to open and calcium floods into pre-synaptic button
4
Q
From Terminal to Synaptic Cleft: 4) Release of Neurotransmitters into Cleft
A
- Some calcium ions attach to the dock causing the vesicle to fuse with the membrane
- This creates fusion pores
- The vesicles releases the neurotransmitters into the synaptic cleft through the fusion pores
- The process of neurotransmitter release is called Exocytosis
- The process of exocytosis lasts around 1-2 milliseconds
5
Q
From Synaptic Cleft to Post-Synaptic Membrane: 5) Attachment & Activation
A
- When the neurotransmitter attaches to the post-synaptic membrane it changes its membrane potential (to allow the signal to continue to the next axon….or not)
- Neurotransmitters only attach to specific binding sites / receptors
- Neurotransmitter that attach to specific binding sites are called Ligands
6
Q
Stopping the Information Flow: 6) Deactivation
A
- Activation does not continue for ever (Axons & synapses would become over-stimulated)
- So once the message is received Synaptic transmission is terminated in 2 ways:
1. Reuptake
2. Enzymatic Breakdown
7
Q
Stopping the Information Flow: 1) Reuptake
A
- Neurotransmitters detach from receptors and are taken back into the pre-synaptic membrane
(The neurotransmitters can then be re-used)
8
Q
Stopping the Information Flow: 2) Enzymatic Breakdown
A
- Specific enzymes destroy the neurotransmitters preventing further activation
9
Q
Neurotransmitters
A
- Neurotransmitters – chemicals that communicate between neurons
- Some neurotransmitters cause Depolarisation at post-synaptic membrane - EPSP
- Some neurotransmitters cause Hyperpolarisation at post-synaptic membrane - IPSP
- Some neurotransmitters are inhibitory, some are excitatory and some are both (depending on their receptors)
10
Q
Neuropeptides
A
- The most common neuropeptides are Endogenous Opioids
- (enkephalins / endorphins) → Slows firing rate of neurons carrying pain signals → Natural pain relief & pleasure
11
Q
Glutamate & GABA
A
- Most communication in brain is carried out by Glutamate & GABA
- Glutamate is Excitatory
(it turns things up) - producing EPSPs - it increases/speeds up - GABA is Inhibitory
(it turns things down) - producing IPSPs - it decreases/slows - Both are abundant in CNS (& also in simple organisms)
12
Q
Glutamate
A
- Synapses that use Glutamate are Glutamatergic Synapses
- Glutamate increases activation by:
1. Causing depolarisation = Excitatory Post Synaptic Potentials (EPSPs)
2. Lowering the threshold required for excitation = Increasing firing rate in neurons
13
Q
GABA
A
- Synapses that use GABA are GABAergic Synapses
- GABA prevents the brain from becoming excessively aroused by:
1. Causing hyperpolarisation = Inhibitory Post Synaptic Potentials (IPSPs)
2. Increasing the threshold required for excitation = Decreasing firing rate in neurons
14
Q
Monoamines
A
- Monoamines are synthesised from a single Amino Acid
- They are most abundant in neurons with cell bodies in the brain stem (lots of dendritic spines to allow increased communication)
- 2 types of Monoamines (classified by structure):
1. Catecholamines - adrenaline, noradrenaline, dopamine
2. Indolamines - serotonin
✳︎ Catechol group - (benzene ring & 2 hydroxyl groups)
15
Q
Catecholamine synthesis
A
- Phenylalanines - e.g. cow, eggs, milk, chicken, fish
- Tyrosine (Amino Acid) - (Tyrosine hydroxyls) → L-Dopa - (Dopa decarboxylase) → Dopamine (Dopamine β-hydroxylase) → Noradrenaline (PNMT) → Adrenaline
✳︎ Each step is pre-cursor to next
16
Q
Dopamine
A
- Synapses that use dopamine are Dopaminergic Synapses
- 3 main dopaminergic systems in the mid-brain:
1. Nigrostriatal System: substantia nigra – neostriatum (part of basal ganglia) - Sensory stimuli, Movement, Balance
2. Mesolimbic System
ventral tegmental area – parts of limbic system - (amygdala, nucleus accumbens) - Reinforcement / Reward & Emotion
3. Mesocortical System
(ventral tegmental area – pre-frontal cortex) - Cognition (ST memory, planning, strategy)
17
Q
Excess dopamine levels
A
- Schizophrenia is associated with excessive dopaminergic activity
- (SOME) schizophrenia treatments reduce symptoms by blocking dopamine action
- Side effects of these treatments include the development of Parkinson’s like symptoms - Tardive Dyskinesia: Involuntary movements of face and/or body
- BUT - dopamine not the only chemical implicated in schizophrenia (other treatments also act on serotonergic systems)
18
Q
Noradrenaline & Adrenaline
A
- Noradrenaline & Adrenaline are neurotransmitters in the brain [Also released as hormones from the Adrenal Medulla]
- Noradrenaline (& Adrenaline) synapses are… Noradrenergic (or Adrenergic) Synapses
- The axons of adrenergic neurons project to most areas of the brain and have effect on wide variety of functions mostly to do with arousal & alertness
✳︎ Cognition
✳︎ Motivation
✳︎ Attention & vigilance
✳︎ (also reward pathways)
19
Q
Indolamines [Serotonin]
A
- Tryptophan (Amino Acid) - (Tryptophan hydroxylase) → 5-hydroxytryptophan (5-HTP) - (5-HTP decarboxylase) → 5-hydroxytryptamine - Serotonin
- Synapses that use serotonin are called Serotonergic Receptors
20
Q
Serotonergic pathways
A
- Serotonergic neurons project to most brain areas notably: ∙ Limbic system ∙ Basal ganglia ∙ Cerebral cortex ∙ (and descend along spinal cord)
21
Q
Serotonin - (some) of the roles of Serotonin
A
- Most serotonergic synapses cause IPSPs
- So, most behavioural effects are inhibitory
- Serotonin important for Sleep regulation
∙ Serotonin depletion decreases sleep duration
∙ Ingesting tryptophan may make you sleepy - Serotonin important for Mood regulation
∙ Serotonin depletion related to depression
∙ Drugs that prevent serotonin re-uptake increase activation on serotonin at the synapse e.g., Selective Serotonin Reuptake Inhibitors (SSRIs)
22
Q
Breakdown & Reuptake of Monoamines
A
- Monoamines are broken down by an enzyme called Monoamine Oxidase (MAO)
- MAO converts excess monoamines into inactive substances
- Drugs that prevent the action of MAO are called Monoamine Oxidase Inhibitors
- These drugs increase levels of monoamines
23
Q
Acetylcholine
A
- Acetylcholine (ACh) is synthesised from Choline & Acetate
- Synapses that use acetylcholine are called Cholinergic Synapses - They are generally excitatory
- The are 2 types of cholinergic receptors:
1. Muscarinic (slower, prolonged reactions)
2. Nicotinic (fast acting responses)
24
Q
Breakdown & Reuptake of Acetylcholine
A
- Choline is transported back into pre-synaptic terminal for future use
- Acetylcholine is broken down by the enzyme acetylcholinesterase (AchE)
- Acetylcholinesterase is abundant in the synaptic cleft to prevent over stimulation → muscle spasm - paralysis
25
Pharmacology and the Synapse
- Many drugs can alter the action of neurotransmitters
- Agonists: Drugs that increase the action of the neurotransmitter
- Antagonists: Drugs that decrease the action of a neurotransmitter
26
Effects on production of neurotransmitters
- L-Dopa is given to Parkinson’s patients to increase release of Dopamine
- α-methyl-ρ-tyrosine (AMPT) inactivates tyrosine hydoxylase preventing synthesis of tyrosine into L-Dopa
∙ Tyrosine (amino acid) - (AMPT - Tyronsine hydroxylase) → L-Dopa - (Dopa decarboxylase) → Dopamine - (Dopamine β-hydroxylase)
27
Effects on storage and release
- Reserpine (traditional use as calming agent & snake-bite anti-venom): Makes vesicles leaky, monoamines leak out of vesicles and are broken down by enzymes
- Black widow spider venom: Stimulates the release of acetylcholine
- Botulinum toxin – Botox: Prevents the release of acetylcholine
28
Effects on receptors
- Nicotine: Mimics acetylcholine at nicotinic receptors
| - Atropine: Blocks muscarinic receptors preventing autonomic functions
29
Effects on degradation and reuptake
- Sarin (nerve agent): Prevents acetylcholine breakdown by destroying acetylcholinesterase (action continues)
- Clozapine (Atypical antipsychotic): Blocks serotonergic & dopaminergic receptors preventing serotonin & dopamine binding with receptors
30
Reward pathways
- The brain-reward pathway is mostly dopaminergic - (ventral tegmental area – limbic system – frontal cortex)
- It makes us feel good when we engage in behaviour necessary for survival: eating, drinking, having sex
- Not surprisingly most drugs (of use & abuse) also work along this pathway
31
Individual differences
- There are large individual differences in drug responsiveness
- Different people have different numbers of receptors which vary in sensitivity depending on genetic & environmental factors
32
some Drugs of Use & Abuse
- Cocaine: Triple Reuptake Inhibitor, Blocks reuptake of catecholamines
- Amphetamines: Increases release of dopamine & noradrenaline (& serotonin in higher doses)
- Heroin: Mimics endogenous opioids stimulating dopamine release
- MDMA (Ecstasy): Low doses – dopamine release, Higher doses – stimulate serotonergic synapses
- Marijuana: Mimics endogenous cannabinoids turning off inhibition of dopamine
- Alcohol: Blocks glutamate activity, Stimulates GABAA receptors
- Methamphetamine (crystal meth): Blocks catecholamine reuptake, Hyperstimulation in CNS (longer duration than cocaine)
33
Hormone basics
- Hormones enable communication between cells
- Hormones are secreted by specialised glands Endocrine Glands
- Hormones are carried in the bloodstream to specific target regions (e.g., other endocrine glands, organs, cells, the brain)
- Not to be confused with Exocrine Glands (secrete products to outside through ducts)
34
Neural & Endocrine Communication
- SIMILARITIES:
∙ Production of chemicals stored for later release
∙ Stimulated to release chemicals
∙ Some chemicals act as hormones & neurotransmitters
∙ React with specific receptors
- DIFFERENCES:
∙ Neural communication is fixed between channels to precise locations; hormonal signalling is more generalised
∙ Neural messages are very rapid; hormonal communication is slower and more prolonged
∙ Neural messages are digitised – they fire or not; hormonal signalling is analogue – the more hormone, the greater the effect
∙ Some neural communication is under voluntary control (e.g., muscle), hormone release is not
35
Summary of Functions
- Hormone: derived from Greek – To excite / set in motion
- But hormones do not just excite they regulate
►Growth & development
►Reproduction
►Metabolism (intake, production and utilisation of energy)
►Maintenance of internal environment (e.g., homeostasis of bodily systems – temperature, sleep)
►Control of internal organs & systems (e.g., regulation of heart rate, blood pressure, immunity)
36
Maintenance of Homeostasis
- Most hormonal release is regulated by process of Negative Feedback
- Output from a gland (hormones) responsible for preventing further release
37
The Pineal Gland (not connecting body and soul)
- Produces Melatonin
| - Entrainment: Matching of a physiological event to an environmental oscillation
38
Control of Hormone Release
- Hormone release generally controlled by 2 key structures in the brain
1. Hypothalamus:
►Located at base of brain
►Hypothalamic Nuclei synthesise Hypothalamic Releasing Hormones that either stimulate or inhibit hormone release from pituitary gland
39
The Pituitary Gland
- Releases Tropic Hormones: Hormones that influence release of hormones from other glands
- Anterior Pituitary: Controlled by Hypothalamic, Releasing Hormones
- Posterior Pituitary: Controlled by nerve stimulation from hypothalamus
40
Posterior Pituitary Gland (1)
- In response to nerve impulse from hypothalamus releases...Anti-diuretic Hormone (ADH / Vasopressin):
►Stimulates the re-absorption of water by kidneys (conserves water as prevents it being lost in urine)
►Stimulates vasoconstriction (> BP in response to stress)
41
Posterior Pituitary Gland (2)
- Oxytocin:
►Causes muscle contraction in uterus (quite handy in childbirth!)
►Stimulates ejection of breast milk (quite handy, but not always!)
- Oxytocin – The Tend & Befriend Hormone:
►Elevated levels during sexual arousal & orgasm
►Levels respond to social stimulation - Causing anti-stress effects (inhibiting stress hormones)
42
Anterior Pituitary Gland (1)
- In response to hypothalamic releasing hormones…
- Growth Hormone – does what it says
►Pre-pubertal deficits – Pituitary Dwarfism
►Pre-pubertal excess - Gigantism
- Thyroid Stimulating Hormone: Stimulates release of Thyroxine by Thyroid Gland
✳︎ If thyroid gland is unable to produce enough thyroxine it swells up in attempt to meet deficit - This is called a Goiter
43
Anterior Pituitary Gland (2)
- Gonadotrophins - Sex Hormone Release
►Luteinizing Hormone: Increases production: ∼Progesterone (ovaries)
∼Testosterone (testes & adrenal cortex)
►Follicle Stimulating Hormone:
Increases production:
∼Estrogen (ovaries)
∼Sperm (testes)
- Adrenocorticotropic Hormone (ACTH) – Stress Hormone Release: Stimulates release of stress hormones from adrenal cortex
44
Anterior Pituitary Gland (3)
- Prolactin:
►Promotes tissue development in breasts during pregnancy
►Stimulates milk production after birth
✳︎Prolactin – The Sexual Desire Hormone? Recent research shows that Prolactin also plays an important role in sexual desire
45
Prolactin & Sexual Desire in Males
- Sustained elevation of prolactin post orgasm…
►Increases sexual satiety / reduces sexual desire
►Decreases likelihood of subsequent erections & orgasms
- Evidence:
1. Multi-orgasmic men – produce significantly less prolactin at orgasm...So, no reduction in desire – ability for more orgasms
2. [some] Impotence treatments (e.g., Cabergoline)
►Decreases prolactin release (Prolactin Antagonist)
►INCREASE Sexual desire
►DECREASE Refractory period (time before able / want to have sex again)
46
The Adrenal Gland
- The Adrenal Glands sit on top of the kidneys
- The Adrenal Glands made up of 2 areas:
1. Medulla (inside) - Responds to nerve impulses from hypothalamus
2. Cortex (outside) - Responds to ACTH (from Anterior Pituitary)
47
The Adrenal Medulla
- Secretes Noradrenaline & Adrenaline
►Increase heart rate
►Constrict peripheral blood vessels
►Glucose release
- Increased blood flow & energy supply to essential areas (e.g., muscles)
- Short-term preparation for stress - Flight Fight Hormones
48
The Adrenal Cortex
- Secretes 3 types of hormones
1. Sex Hormones (Androgens & Estrogens) But mostly secreted by Testes & Ovaries
2. Mineralocorticoids - Aldosterone - Helps kidneys retain sodium & excrete potassium
✳︎ Maintains blood pressure
✳︎ Maintains balance of salt & water in the body
3. Corticosteroids (Stress hormones) - Principally Cortisol - Maintains essential responses during stressful events
49
The Pancreas
- The pancreas secretes 2 main hormones: Insulin, Glucagon
50
The Testes
- The testes secrete Male Sex Hormones (Androgens)
- Also secreted in small amounts from Adrenal Cortex (so also produced by women)
- The main Androgen is Testosterone
- Production begins during foetal development (organisational effect on sex)
- Testosterone burst at puberty stimulates male secondary characteristics
►Growth & development of male reproductive structures
►Increased skeletal & muscle growth
►Enlargement of larynx (& voice changes)
►Increased body hair
►Sexual drive
51
The Ovaries
- Ovaries secrete Female Sex Hormones (Estrogens)
- Also secreted in small amounts from Adrenal Cortex
(so also produced by men)
- At onset of puberty (female secondary characteristics)
- Estradiol:
►Breast development
►Distribution of fat (hips, legs, breasts)
►Maturation of uterus & vagina
- Progesterone:
►Thickens lining of uterus in pregnancy
- Progesterone & Estradiol:
►Stimulate changes in uterus during menstrual cycle
►Sexual behaviour
52
Hormones & Behaviour
- Hormones do NOT cause a particular behaviour to change…They change the likelihood of behaviours occurring in appropriate contexts
- Certain behaviours / stimuli can also influence hormone levels e.g., Cortisol levels increase when you get stressed during exams - Testosterone levels increase when a contest has been won
✳︎ BUT - Which comes first – the behaviour or the hormonal change
53
Ventral
Toward the front of the body or towards the bottom of the head
54
Dorsal
Toward the back of the body, or towards the top of the head
55
Anterior / Rostral
Nose end
56
Posterior / Caudal
Tail end
57
Lateral
Towards the sides
58
Medial
Towards the middle
59
Bilateral
On both sides of the body or head
60
Ipsilateral
On the same side of the body or head
61
Contralateral
On the opposite side of the body or head
62
Anatomical Planes
- You create a horizontal section when you cut a bread roll for a burger
- You create a sagittal section when you cut a baguette in half (down the middle from the top)
- You create a coronal section when you slice bread
63
Blood Supply to the CNS
- A vast circulatory system...to ensure constant supply of resources
64
Fact Time
- The brain cannot store glucose…it relies on constant supply of blood for glucose & O2
- 1 sec interruption in supply uses ALL of the brain’s resources
- 6 sec interruption causes unconsciousness
- A few minutes interruption can cause brain damage
65
Protecting the CNS (1): Skull & Spine
The Brain & Spinal Cord are delicate & require protection
66
Protecting the CNS (2): Meninges
Between skull & brain / spinal cord & spinal column
67
Meningitis
Infection / inflammation of the meninges
68
Protecting the CNS (3): Blood-Brain Barrier (BBB)
- The CNS cannot kill viruses
- BBB keeps out harmful substances (viruses / bacteria / harmful chemical)
- Small / uncharged molecules (O2 / CO2) can pass through
- Active transport system pumps essentials into brain - glucose / amino acids / vitamins / hormones
69
Protecting the CNS (4): The Ventricular System
- The brain floats in a bath of protective fluid (Cerebrospinal Fluid – CSF)
- CSF flows around:
- Subarachnoid space (meninges) - 4 ventricles (little bellies) in the brain
70
The Central Nervous System
- Forebrain
- Midbrain
- Hindbrain
71
Hindbrain: Myelencephalon; Medulla oblongata (Medulla)
- Control of vital functions:
- Cardiovascular system
- Respiration
- Muscle tone
....through receiving information on heart rate, blood pressure, O2 and CO2 levels
72
Hindbrain: Metencephalon; The pons (bridge)
- Serves as link (bridge) between hindbrain & midbrain
- Also involved in:
- Respiration
- Eye movement
- Facial expressions
- Chewing
73
Hindbrain: Metencephalon; Cerebellum (little brain)
- Communicates to motor cortex & sense organs:
- Voluntary muscle movement
- Maintenance of balance & equilibrium
- Muscle tone & posture
74
Midbrain: Mesencephalon;
| Tectum (roof) & Tegmentum (covering)
- Major pathway for sensory & motor impulses between forebrain & hindbrain
- Tectum: Auditory & visual communication
- Tegmentum: Sensory processes, movement, motor control (substantia nigra)
75
Forebrain
- Telencephalon (the hemispheres)
| - Diencephalon (interbrain)
76
Forebrain: Diencephalon
- Thalamus (chamber): Receives sensory information & relays to sensory processing in cortex
- Hypothalamus - Connected to Pituitary gland: Regulation of ANS and Endocrine System
77
Forebrain: Telencephalon (the hemispheres)
- Corpus callosum: Nerve fibres that connect he hemispheres
- White Matter: axons covered in myelin sheath
- Grey Matter: Cortex made up of cells
78
Forebrain - Telencephalon
- The Limbic System: A group of structures involved in stress & emotion, memory storage & retrieval
- Cingulate Gyrus: Control of emotional behaviour
- Fornix: Links hippocampus to hypothalamus
- Amygdala: Emotional processing & motivation
- Hippocampus: Involved in learning & memory (detection of threat / emotionally charged memories
79
Forebrain: Bumps & Grooves
- 3 major grooves divide the cortex: Longitudinal fissure, Central sulcus, Lateral fissure
80
Forebrain: The grooves form 4 major divisions (lobes)
- Central sulcus divides the frontal lobe from the parietal lobe,
- Lateral fissure divides the temporal lobe from the frontal & parietal lobes
- Frontal lobe
- Parietal lobe
- Temporal lobe
- Occipital lobe
81
Forebrain - Telencephalon; Cerebral Cortex
- These lobes form the structure of the cortex
- Frontal lobe
- Parietal lobe
- Temporal lobe
- Occipital lobe
