Biopsychology

Divisions of the Nervous system

The Nervous system is broken down into two subsystems: the peripheral and central nervous system. The peripheral nervous system then divides into the autonomic and somatic nervous system, and the central nervous system is made up of the brain and spinal cord. The ANS is also made up of the sympathetic and parasympathetic NS.

Peripheral nervous system

Consists of all the neurons outside the CNS. It relays impulses to and from the CNS and the rest of the body.

Autonomic nervous system

Governs internal vital functions e.g. homeostasis, and controls smooth muscle and glands. Dictates involuntary/unconscious actions

Somatic nervous system

Carries sensory info into the brain, and motor info from the CNS to the skeletal muscles. Controls some voluntary/conscious control

Brain

Provides conscious awareness, and is involved in all psychological processes

Spinal cord

Transfers messages to and from the brain, and is responsible for simple reflex actions

Label from left to right

1. Dendrites

2. Axon

3. Axon terminal

4. Cell body

5. Nodes of Ranvier

6. Nucleus

7. Myelin sheath

8. Shwann cells

Dendrites

Carry electrical impulses towards cell body + are the location of neurotransmitter receptor sites

Axon

Carry impulses over distance, can be myelinated, end in terminals where neurotransmitters are stored

Nodes of Ranvier

Allow for further transmission of impulses

Terminal buttons

Neurotransmitters (stored in vesicles) are released from here

Sensory neurons: Function, connections to cell body, myelinated?

Detect impulses from a receptor, 2, yes

Relay neurons: Function, connections to cell body, myelinated?

Relay signal from sensory neuron to motor neuron, 1, no

Motor neurons: Function, connections to cell body, myelinated?

Signal from CNS to effector, 1, yes

Path of an impulse through the nervous system

Sensory neuron » cell body » Axon/nodes of ranvier » Relay neuron » cell body » Dendrites » Motor neuron » Axon/nodes of ranvier » Synapse with effector

Main differences between nervous and endocrine system

• Messages: NS travel in neurons electrically, ES in bloodstream chemically

• Reaction: NS is fast and short, ES is slow and long

• NS messages target cells, EC messages target organs

Fight or flight (FoF) explained

In dangerous situations the amygdala gets activated, which responds to sensory input and connects it with emotions associated with FoF. If the situation is deemed as stressful, the amygdala sends a distress signal to the hypothalamus, which communicates with the body through the sympathetic nervous system. If the situation required a short-term response the sympathomedullary (SAM) pathway is activated, triggering FoF. This pathway activates the adrenal glands to produce adrenaline (hormone) and noradrenaline (NT).

Physiological changes of FoF

• HR increases and coronary blood vessels dilate so more blood gets pumped around the body

• BR increases and bronchi dilate so muscles receive more oxygen

• Increased conversion of glycogen to glucose so more energy

• Pupils dilate to allow more light into eyes

Research against FoF

Gray (1998) - suggests the first response to danger is to avoid confrontation altogether, which is shown by a freeze response. This is a problem for FoF as it suggests the theory is inaccurate because it doesn’t explain this.
Taylor et al. (2000) - women are more likely to tend and befriend rather than FoF. So the FoF theory is androcentric