Biopsychology

Question 1

The Nervous system and the endocrine system: Define Nervous system

Answer 1

Consists of the central nervous system and the peripheral nervous system. Communicates using electrical signals.

Question 2

The Nervous system and the endocrine system: Define Central Nervous System (CNS)

Answer 2

Consists of the brain and the spinal cords and is the origin of all complex commands and decisions.

Question 3

The Nervous system and the endocrine system: Define Peripheral nervous system (PNS)

Answer 3

Sends information to the CNS from the outside world, and transmits messages from the CNS to muscles and glands in the body.

Question 4

The Nervous system and the endocrine system: Define Somatic nervous system (SNS)

Answer 4

Transmits information from receptor cells in the sense organs to the CNS. It also receives information from the CNS that directs muscles to act.

Question 5

The Nervous system and the endocrine system: Define Autonomic nervous system (ANS)

Answer 5

Transmits information to and from internal bodily organs. It is ‘autonomic’ as the system operates involuntarily. It has 2 main divisions: the sympathetic and parasympathetic.

Question 6

The nervous system info

Answer 6

The nervous system is a specialised network of cells in the human body and is our primary internal communication system. It is based on electrical and chemical signals whereas the endocrine system is based on hormones.

The nervous system has two main functions:

• To collect, process and respond to information in the environment.
• To co-ordinate the working of different organs and cells in the body.

The nervous system is divided into two subsystems:

• Central nervous system (CNS)
• Peripheral nervous system (PNS)

Question 7

The nervous system: The Central nervous system (CNS)

Answer 7

The CNS is made up of the brain and the spinal cord.

• The brain is the centre of all conscious awareness. The brain’s outer layer, the cerebral cortex, is only 3 mm thick and covers the brain like an orange peel covers the orange.
  It is only found in mammals.

The brain is highly developed in humans and is what distinguishes our higher mental functions from those of other animals. Only a few living creatures-sponges and jellyfish do not have a brain.

The brain is divided into 2 hemispheres.

• The spinal cord is an extension of the brain. It passes messages to and from the brain and connects nerves to the PNS. It is also responsible for reflex actions such as pulling your hand away from a hot plate.

Question 8

The nervous system:The peripheral nervous system (PNS)

Answer 8

The PNS transmits messages, via millions of neurons (nerve cells), to and from the central nervous system. The peripheral nervous system is further subdivided into the:

-Autonomic nervous system (ANS) governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses.

• Somatic nervous system (SNS) governs muscle movement and receives information from sensory receptors.

Question 9

The Nervous system and the endocrine system: Define Endocrine system

Answer 9

One of the body’s major information systems that instructs glands to release hormones directly into the bloodstream. These hormones are carried towards target organs in the body. Communicates via chemicals.

Question 10

The Nervous system and the endocrine system: Define Gland

Answer 10

An organ in the body that synthesises substances such as hormones.

Question 11

The Nervous system and the endocrine system: Define Fight or flight response

Answer 11

The way an animal responds when stressed. The body becomes physiologically aroused in readiness to fight an aggressor or, in some case, flee.

Question 12

The Nervous system and the endocrine system: Define Adrenaline

Answer 12

A hormone produced by the adrenal glands which is part of the human body’s immediate stress response system. Adrenaline has a strong effect on the cells of the cardiovascular system- stimulation heart rate, contracting blood vessels and dilating air passages.

Question 13

The endocrine system: Glands and hormones

Answer 13

The endocrine system works alongside the nervous system to control vital functions in the body. The endocrine system acts more slowly than the nervous system but has very widespread and powerful effects. Various glands in the body, such as the thyroid gland, produce hormones. Hormones are secreted into the bloodstream and affect any cell in the body that has a receptor for that particular hormone.

Most hormones affect cells in more than one body organ, leading to many diverse and powerful responses. For example, the thyroid gland produces the hormone thyroxine. This hormone affects cells in the heart (increases heart rate). It also affects cells throughout the body increasing metabolic rates ( the chemical processes taking place in the cells). This in turn affects growth rates.

The key endocrine gland is the pituitary gland, located in the brain. It is often called the ‘master gland’ because it controls the release of hormones from all the other endocrine glands in the body.

Question 14

The endocrine system: Endocrine and ANS working together: Fight or flight

Answer 14

Often the endocrine system and the autonomic system (ANS) work in parallel with one another, for instance during the stressful event. When a stressor is perceived the first thing that happens is a part of the brain called hypothalamus activates the pituitary gland and this triggers activity in the sympathetic branch of the autonomic nervous system. The ANS changes from its normal resting state. (The parasympathetic state) to the physiologically around sympathetic state.

(Adrenaline)
The stress hormone adrenaline is released from the adrenal medulla ( a part of the adrenal gland lying near your kidneys) into the bloodstream. Adrenaline triggers physiological changes in the body (e.g. increased heart rate) which creates the physiological arousal necessary for the fight or flight response.

(Immediate and automatic)
All of this happens in an instant as soon as the threat is detected (for example your heart starts beating faster almost as soon as you experience a fright). This is an acute response and an automatic reaction in the body. The physiological changes associated with this sympathetic response. These changes explain why stress, panic, or even excitement, are often experienced as a ‘sick’ feeling (butterflies in your stomach).

(Parasympathetic action)
Finally, once the threat has passed, the parasympathetic nervous system returns the body to its resting state. The parasympathetic branch of the ANS works in opposition to the sympathetic nervous system- the actions are antagonistic to the sympathetic system. The parasympathetic system acts as a ‘brake’ and reduces the activities of the body that were increased by the actions of the sympathetic branch. This is sometimes referred to as the rest and digest response.

Question 15

Neurons and synaptic transmission: Define Neuron

Answer 15

The basic building blocks of the nervous system, neurons are nerve cells that process and transmit messages though electrical and chemical signals.

Question 16

Neurons and synaptic transmission: Define Sensory neurons

Answer 16

These carry messages from the PNS (peripheral nervous system) to the CNS (central nervous system). They have long dendrites and short axons.

Question 17

Neurons and synaptic transmission: Define Relay neurons

Answer 17

These connect the sensory neurons to the motor or other replay neurons. They have short dendrites and short axons.

Question 18

Neurons and synaptic transmission: Define Motor neutrons

Answer 18

These connect the CNS to effectors such as muscles and glands. They have short dendrites and long axons.

Question 19

Neurons and synaptic transmission-The structure and function of neurons info

Answer 19

There are 100 billion neurons (nerve cells) in the human nervous system, 80% of which are located in the brain. By transmitting electrically and chemically, these neurons provide the nervous system with its primary means of communication.

Question 20

Neurons and synaptic transmission- Types of neurons

Answer 20

Sensory, relay and motor

Question 21

Neurons and synaptic transmission- The structure of a neuron

Answer 21

Neurons vary in size from less than a millimetre to up to a metre long, but all share the same basic structure.

The cell body (or soma) includes a nucleus, which contains the genetic material of the cell. Branchlike structures called dendrites protrude from the cell body. These carry nerve impulses from neighbouring neurons towards the cell body.

The axon carries the impulses away from the cell body down the length of the neuron. The axon is covered in fatty layer of myelin sheath that protects the axon and speeds up electrical transmission of the impulse.

If the myelin sheath was continuous this would have the reverse effect and slow down the electrical impulse. Thus, the myelin sheath is segmented by gaps called nodes of Ranvier. These speed up the transmission of the impulse by forcing it to ‘jump’ across the gaps along the axon.

Finally, at the end of the axon are terminal buttons that communicate with the next neuron in the chain across a gap known as the synapse.

Question 22

Neurons and synaptic transmission- Location of neurons

Answer 22

The cell bodies of neurons may be in the central nervous system (CNS) but they have long axons which form part of the peripheral nervous system (PNS). Sensory neurons are located outside of the CNS, in the PNS in clusters known as ganglia. Relay neurons make up 97% of all neurons and most are found within the brain and the visual system.

Question 23

Neurons and synaptic transmission- Electrical transmission (the firing of a neuron)

Answer 23

When a neuron is in a resting state the inside of the cell is negatively charged compared to the outside. When a neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split second causing an action potential to occur. This creates an electrical impulse that travels down the axon towards the end of the neuron.