Biopsychology

Question 1

The Nervous System

Answer 1

Nervous system - A specialised network of cells, fast-acting and electrical (and chemical) internal communication system.

Central nervous system (CNS) -
Brain - divided into hemispheres, cerebral cortex (outer layer), 3mm thick.
Spinal cord - connects brain to PNS, reflexes.

Peripheral nervous system (PNS) - Autonomic nervous system (ANS) - governs vital functions.
Somatic nervous system (SNS) - muscle movement, sensory information.

Question 2

The endocrine system

Answer 2

Glands and hormones - Glands produce hormones
Hormones distributed in bloodstream, e.g. thyroid gland produces thyroxine.
Pituitary is the master gland.

Fight or flight -
Sympathetic arousal: hypothamalus + pituitary > adrenal gland > adrenaline.
Adrenaline leads to increased heart rate, faster breathing, sweating, inhibits digestion.
Immediate and automatic.
Parasympathetic state - once threat has passed, body returns to rest and digest.

Question 3

Structure and function of neurons

Answer 3

Types of neurons:
Sensory - PNS to CNS, long dendrites - short axons.
Relay - sensory to motor or other, short - short.
Motor - CNS to effectors, short - long.

Structure of a neuron -
Cell body contains nucleus, has dendrites.
Axon covered in myelin sheath divided by nodes of Ranvier.

Electrical transmission - Positive charge leads to action potential.

Question 4

Synaptic transmission

Answer 4

Synapse - Neurons separated by very tiny gap.

Chemical transmission - Neurotransmitter released from synaptic vesicle into synapse, taken up by postsynaptic receptor site on receiving dendrite.

Neurotransmitters - Specialist functions e.g. acetylcholine for muscle contraction.

Excitation and inhibition - Adrenaline is excitatory, serotonin is inhibitory.

Summation - Impulses are ‘added up’, net effect is excitatory on inhibitory.