PSY 202

Question 1

Explain the neuronal transmission

Answer 1

1. RESTING MEMBRANE POTENTIAL
   - The neuron is at rest and not sending any signals.
   - Inside of the neuron is more negative than the outside (about -70 mV)
   - The Sodium-Potassium pump keeps this balance (pumps 3 Na⁺ out and pumps 2 K⁺ in
   - This creates and maintains the resting potential
2. STIMULUS REACHES THE NEURON
   - A stimulus causes the sodium channels to open
   - If enough sodium enters, the charge inside becomes less negative
   - If it reaches the threshold (about -55 mV), the neuron fires an action potential
3. DEPOLARIZATION
   - More Na⁺ ions rush into the neuron
   - Inside becomes positive (up to about +30mV)
   - This is the action potential - the nerve impulse has started
4. REPOLARIZATION
   - Potassium (K⁺) channels open, and K⁺ rushes out of the neuron
   - The inside becomes negative again - returning toward resting potential
5. RETURN TO RESTING STATE
   - Sodium-Potassium pump restores original ion balance
   - Neuron returns to -70 mV and is ready to fire again

Question 2

Explain synaptic transmission

Answer 2

An electrical signal (action potential) travels down the axon of the presynaptic neuron to the axon terminal. The action potential triggers voltage-gated calcium (Ca²⁺) channels to open and calcium ions flow into the axon terminal. The influx of calcium causes synaptic vesicles to move towards the membrane. These vesicles fuse with the presynaptic membrane and release neurotransmitters into the synaptic cleft. Neurotransmitters diffuse across the synaptic cleft and they bind to specific receptors on the postsynaptic membrane of the next neuron. Binding causes ion channels to open in the postsynaptic neuron and this generates a new electrical signal (either excitatory or inhibitory) depending on the neurotransmitter and receptor. To stop the signal, neurotransmitters may be broken down by enzymes or reabsorbed by the presynaptic neuron or simply diffuse away from the synaptic cleft.

Question 3

Parts of a neuron and their functions

Answer 3

1. Axon - tube like structures that transmit information from the cell body to the terminal buttons
2. Dendrites - Receive information from other neurons
3. Cell body/Soma - It is the brain of the neuron, making up gray matter, and containing the nucleus
4. Axon hillock - Connects the cell body to the axon
5. Myelin sheath - insulates the electric impulse and allows information to travel faster
6. Nodes of Ranvier
7. Terminal buttons/Axon terminals - where information from the axon ends up and contains neurotransmitters
8. Synapse/Synaptic cleft - gap between neurons
9. Neurotransmitters - chemicals in the axon terminal that attempt to communicate with dendrites on other neurons

Question 4

Parts of the brain and their functions

Answer 4

1. Cerebrum
   Function: Controls voluntary actions, thinking, learning, memory, emotion, and sensory processing.

Divided into lobes:
- Frontal lobe: Decision-making, problem-solving, movement, speech.
- Parietal lobe: Sensory information like touch, temperature, and pain, spatial awareness, and navigation.
- Temporal lobe: Hearing, language, memory.
- Occipital lobe: Vision.

2. Cerebellum
   Function: Coordination and balance, posture, and fine motor movements. It is located under the cerebrum at the back of the head.
3. Brainstem
   Parts: Midbrain, pons, medulla oblongata.

Function: Controls automatic functions like heartbeat, breathing, and digestion. Connects the brain to the spinal cord.

4. Limbic System
   Includes: Hippocampus, amygdala, hypothalamus.

Function: Regulates emotions, memory, and motivation.

• Hippocampus: Memory formation and storage
• Amygdala: Emotions like fear and aggression.
• Hypothalamus: Controls hunger, thirst, sleep, body temperature, and the endocrine system.

5. Thalamus
   Function: Acts as a relay station, sending sensory and motor signals to the cerebral cortex.
6. Corpus Callosum
   Function: Connects the left and right hemispheres of the brain and enables communication between them.

Question 5

What is the nervous system?

Answer 5

The nervous system is the body’s control center, responsible for coordinating actions and sensory information. It receives information from the senses, processes it, and sends signals to muscles and organs to respond appropriately.

Question 6

Main parts of the nervous system

Answer 6

• Central nervous system: The control centre of the body and it includes the brain and spinal cord.
• Peripheral nervous system: The nerves that branch out from the brain and spinal cord. It includes sensory neurons that bring in messages and motor neurons that carry instructions to muscles and glands. The PNS is divided into the somatic nervous system that controls voluntary movements and the autonomic nervous system that controls involuntary functions. The autonomic system is further divided into sympathetic nervous system that prepares the body for action and the parasympathetic nervous system that calms the body down

Question 7

What is a neuron?

Answer 7

A specialised cell in the nervous system responsible for transmitting information through electrical and chemical signals.

Question 8

What is a nerve impulse/action potential?

Answer 8

A nerve impulse is an electrical signal that travels along the surface of a neuron, used to pass information through the nervous system.

Question 9

What is saltatory conduction?

Answer 9

Saltatory conduction is when an action potential jumps from one node of ranvier to the next.

Question 10

What is impulse transmission?

Answer 10

Impulse transmission is the process by which nerve impulses move from one neuron to another or from a neuron to a muscle or gland. There are electrical and chemical Impulses.

Question 11

Functions of the CNS

Answer 11

1. Processing information
2. Controlling responses
3. Coordinating body functions
4. Storing and retrieving memory
5. Regulating emotions and behaviour
6. Maintaining homeostasis

Question 12

What is homeostasis?

Answer 12

Homeostasis is the process by which the body maintains a stable internal environment despite changes in the external environment.

Question 13

Types of cells in the NS

Answer 13

Neurons and glial cells

Question 14

What is the all or none law?

Answer 14

The all or none law refers to the principle that a neuron either fires completely or not at all when it is stimulated.

Question 15

Nervous system disorders

Answer 15

1. Alzheimer’s disease (memory loss)
2. Parkinson’s disease (Movement issues)
3. Multiple sclerosis (Nerve damage)
4. Stroke (Brain blood supply problems)

Question 16

What is neuroplasticity?

Answer 16

Neuroplasticity is the brain’s ability to change, adapt, and reorganise itself by forming new neural connections, especially after brain damage or injury.

Question 17

Types of plasticity after brain damage

Answer 17

1. AXONAL SPROUTING - Undamaged neurons grow new nerve endings (axons) to reconnect with neurons whose links were lost due to injury
2. FUNCTIONAL REORGANIZATION - When functions previously carried out by a damaged brain area are reassigned to other undamaged areas. Types include, inter hemispheric, intra hemispheric, compensatory reorganization.
3. SYNAPTOGENESIS - The formation of new synapses between neurons
4. NEUROGENESIS - The birth of new neurons from stem cells, mostly in the hippocampus.

Question 18

Factors influencing plasticity

Answer 18

• Age
• Extent of damage
• Rehabilitation
• Time since injury

Question 19

Examples of plasticity

Answer 19

• Stroke recovery
• Blindness and sensory rewiring
• Phantom limb sensation
• Childhood brain injury

Question 20

What is short-term brain recovery?

Answer 20

Short-term brain recovery refers to the initial healing and adaptation process that occurs in the days to weeks following brain injury.

Question 21

Phases of short-term brain recovery

Answer 21

1. Acute phase (0 to 48 hours)
   The brain reduces swelling and removes dead or damaged tissue. Blood flow begins to normalize.
2. Subacute phase (3 days to 4 weeks)
   Neurochemical balance begins to return
   Damaged but still viable neurons may regain function

Question 22

What is a stroke?

Answer 22

A stroke, also known as a Cerebrovascular accident, occurs when the blood supply to part of the brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients. Brain cells begin to die within minutes, which can cause lasting brain damage, long-term disability, or even death.

Question 23

Types of stroke

Answer 23

1. Ischemic stroke: Caused by a blood clot or blockage in a blood vessel supplying the brain. The blockage could be a result of;
   - Atherosclerosis- Buildup of fatty plaques in arteries
   - Clots formed in narrow brain arteries
   - Embolism- A clot or debris from the heart travels to the brain
   - Atrial fibrillation- Irregular heartbeat causes clots to form in the heart
2. Hemorrhagic stroke: Caused by a burst blood vessel that bleeds into the brain. Often due to high blood pressure, trauma, or aneurysm.
3. Transient Ischemic Attack: A mini-stroke caused by a temporary blockage. Symptoms last less than 24 hours and go away on their own, but it’s a warning sign of a possible future stroke.

Question 24

Processes involved in stroke recovery

Answer 24

• Neuroplasticity
• Axonal sprouting
• Synaptogenesis
• Diaschisis resolution: Remote but connected brain areas that were suppressed begin to reactivate.
• Unmasking latent pathways: Previously unused neural circuits become active

Question 25

What are chemical senses?

Answer 25

Chemical senses are the senses that detect chemical stimuli in the environment. The are two main chemical senses; Olfaction and Gustation.

Question 26

What is the gustatory system?

Answer 26

The gustatory system is the sensory system responsible for taste. It detects chemicals in food and drinks through taste buds on the tongue.

Question 27

What are tastants?

Answer 27

Tastants are the actual chemical molecules that trigger taste sensations by interacting with your taste buds.

Question 28

What is a taste receptor?

Answer 28

A taste receptor cell is a specialised epithelial cell that detects and transmits various taste stimuli to the brain.

Question 29

What are papillae?

Answer 29

Papillae are the tiny bumps on the tongue that contain taste buds.

Question 30

Types of papillae

Answer 30

1. FUNGIFORM PAPILLAE: Found mostly on the tip and sides of the tongue and contain 3 to 5 taste buds in each papilla. 2. CIRCUMVALLATE PAPILLAE: Large, dome-shaped, form a v shape at the back of the tongue, and contain many taste buds 3. FOLIATE PAPILLAE: Leaf like folds on the sides of the tongue. The tongue has about 20, each of which has several hundred taste buds.

Question 31

Types of taste receptor cells

Answer 31

1. TYPE I CELLS: Detects salty tastes by managing sodium ions. 2. TYPE II CELLS: Used G-protein coupled receptors to detect sweet, umami, and bitter tastes. 3. TYPE III CELLS: Respond to acids through direct ion flow. Detects sour tastes 4. TYPE IV CELLS: Represent stem or progenitor cells

Question 32

Types of tastants

Answer 32

1. Sweet - Indicate energy-rich nutrients like sugars. 2. Salty - Help regulate electrolyte balance 3. Sour - Signal acidity, which may indicate spoilage 4. Bitter - Serve as a warning signal for toxins 5. Umami - Detect proteins and amino acids

Question 33

How tastants work

Answer 33

Salt receptors detect salty tastes when sodium ions enter the taste cell and trigger a response. Sour receptors respond to acids when hydrogen ions block potassium channels, exciting the cell. Sweet, bitter, and umami receptors use special proteins that, when activated by certain molecules, start a chain reaction that leads to a taste signal.

Question 34

What are taste buds?

Answer 34

A taste bud is a collection of taste or gustatory receptor cells grouped inside the papillae.

Question 35

Process of taste perception

Answer 35

- Molecules from food dissolve in saliva and interact with taste receptors in the mouth and throat. - Taste buds are made up of receptor cells with microvilli that detect these molecules. - When molecules bind to receptors on the microvilli, it causes chemical changes that lead to neural signals. - These signals travel to the brain through different nerves (based on where in the mouth the signal originates). - Taste buds regenerate every 10–14 days, so mild damage (like burning your tongue) is temporary. - Taste signals go to the medulla, thalamus, limbic system, and finally the gustatory cortex for processing.

Question 36

Cranial nerves involved in taste

Answer 36

Facial (VII), Glossopharyngeal (IX), and Vagus (X)

Question 37

What is vision?

Answer 37

Vision is the special sense that is based on the transduction of light stimuli received through the eyes.

Question 38

Parts of the eye

Answer 38

1. Cornea – The clear, outer covering that bends (refracts) light into the eye. 2. Pupil – The black opening in the centre that lets light in. 3. Iris – The colored part of the eye that controls the size of the pupil. 4. Lens – Focuses light onto the retina by changing shape. 5. Retina – The inner layer at the back of the eye that contains photoreceptors (rods and cones) to detect light. 6. Optic nerve – Carries visual information from the retina to the brain. 7. Sclera – The white outer layer that protects the eye.

Question 39

Functions of the eye

Answer 39

1. Detecting lights and colours 2. Focusing images 3. Perceiving depth 4. Identifying objects 5. Interacting with the world

Question 40

Steps in the visual process

Answer 40

Light enters the eye through the cornea. It passes through the pupil, which is controlled by the iris to adjust light entry. The lens bends and focuses the light onto the retina. Photoreceptors in the retina convert light into electrical signals. These signals are processed by retinal neurons and sent through the optic nerve. The optic nerves from both eyes meet at the optic chiasm, where some nerve fibers cross. Signals continue to the lateral geniculate nucleus (LGN) in the thalamus. From the thalamus, signals go to the primary visual cortex in the occipital lobe of the brain. The brain interprets the signals, allowing us to see.

Question 41

What is perception?

Answer 41

Perception is the process by which the brain organises and interprets sensory information, turning raw data from our senses (like sight, sound, or touch) into meaningful experiences.

Question 42

Aspects of visual perception

Answer 42

1. Object recognition 2. Depth perception 3. Colour perception 4. Motion perception 5. Figure-ground segregation 6. Contextual interpretation

Question 43

Scope of research methods in physiological psychology

Answer 43

1. Brain and behaviour 2. Nervous system functions 3. Neurotransmitters and hormones 4. Genetics and heredity 5. Mental health

Question 44

Categories of research methods in physiological psychology

Answer 44

1. EXPERIMENTAL METHODS These involve changing something in the brain to see what happens to behavior or body responses. - Lesion studies: Destroy a brain part and see what behavior changes. - Stimulation studies: Stimulate a brain area to see what it controls. - Electrical stimulation: Send electricity to a brain part. - Optogenetics: Use light to turn specific neurons on/off. - TMS: A non-invasive way to temporarily activate or shut down brain regions in humans. 2. NEUROIMAGING TECHNIQUES These help us see the brain without surgery. - MRI: Very detailed picture using magnets. - CT scan: Uses X-rays to show brain injuries or tumors. - fMRI: Measures blood flow; more blood = more activity. - PET scan: Uses a small radioactive tracer to track brain activity. 3. ELECTROPHYSIOLOGICAL RECORDING These record the brain’s electrical signals. - EEG: Electrodes on the scalp record brain waves. - ERP: Special kind of EEG that shows how the brain responds to a sound, picture, etc. - Single-unit recording: Records from a single neuron using a tiny wire. 4. BEHAVIORAL AND COGNITIVE TESTING These study what someone does or how they think, to understand the brain. - Animal models: Rats/mice used in mazes to test learning and memory. - Human tasks: Tests like the Stroop test for attention or fear conditioning to study emotions. 5. CORRELATIONAL METHODS These look at relationships (but don’t prove cause). For example, to check if people with a bigger amygdala are more aggressive. You’re not changing anything, just seeing if two things are linked. 6. NEUROCHEMICAL ANALYSIS This checks the chemicals in the brain or body. - Measures things like neurotransmitters (e.g., dopamine, serotonin) or hormones. - Can help understand mood, behavior, or drug effects.

Question 45

Challenges and limitations in research

Answer 45

- Complexity of the brain - Translational issues - Technological constraints - Ethical restrictions

Question 46

What is auditory processing?

Answer 46

Auditory processing refers to how the brain interprets and makes sense of the sounds we hear.

Question 47

Parts of the ear

Answer 47

1. OUTER EAR Pinna (Auricle): The visible part of the ear that collects sound waves. Ear Canal: A Tube that directs sound waves to the eardrum. Tympanic Membrane (Eardrum): Vibrates when sound waves hit it. 2. MIDDLE EAR Ossicles (Three tiny bones): Malleus (Hammer) Incus (Anvil) Stapes (Stirrup) Eustachian Tube: Balances air pressure between the middle ear and throat. 3. Inner Ear Cochlea: Spiral-shaped organ that transforms sound vibrations into nerve signals. Semicircular Canals: Help with balance, not hearing. Auditory Nerve (Cochlear Nerve): Carries electrical signals from the cochlea to the brain.

Question 48

How hearing works

Answer 48

- Sound travels through the air as vibrations (waves). - These waves enter the outer ear (pinna) and move down the ear canal. - The sound waves cause the eardrum (a thin membrane) to vibrate. - The vibration is passed to three small bones in the middle ear: Malleus, Incus, and Stapes - These bones amplify the sound and send it to the inner ear. - The cochlea is a spiral-shaped, fluid-filled organ in the inner ear. - Inside it are tiny hair cells that move when the fluid vibrates. - These movements turn into electrical signals. - The auditory nerve carries the signals to the auditory cortex in the temporal lobe of the brain. - The brain then interprets the signals as sounds.

Question 49

Functions of the PNS

Answer 49

1. Connects the CNS to limbs and organs by carrying signals between the brain/spinal cord and the rest of the body. 2. Controls voluntary movements through the somatic nervous system (e.g., moving your hand). 3. Regulates involuntary functions like heartbeat and digestion via the autonomic nervous system. 4. Detects sensory input such as touch, pain, temperature, and sends it to the CNS. 5. Maintains homeostasis by adjusting internal processes through sympathetic and parasympathetic branches.