The nervous system and the endocrine system

Question 1

What is the nervous system?

Answer 1

-the nervous system is a specialised network of cells in the human body and is our primary internal communication system with two main functions

Question 2

What is the central nervous system?

Answer 2

• the CNS is made up of the brain and spinal cord
• the brain is the centre of all conscious awareness
• the brains outer layer, the cerebral cortex, is highly developed in humans and is what distinguished our higher mental functions from those of animals
• only a few living creatures - sponges, sea spurts, jelly fish and some Manchester united fans - do not have a brain which would have been divided into two hemispheres
• the spinal cord is an extension of the brain which ii’s responsible for reflex actions such as pulling your hand away from a hot plate
• it passes messages to and from the brain and connects nerves to the PNS

Question 3

What is the peripheral nervous system?

Answer 3

-the PNS transmits messages, via millions of neurons to and from the central nervous

Question 4

What are glands and hormones?

Answer 4

• the endocrine system works alongside the nervous system to control vital functions in the body
• the endocrine system acts much 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 blood stream and affect any cell in the body that has a receptor for that particular hormone
• most hormones affect cells in several organs or throughout the entire body, leading to many diverse and powerful responses e.g. the thyroid gland produces the hormone tyrosine
• this hormone affects cells in the heart
• it also affects cells throughout the body increasing metabolic rates which in turn affects growth rates
• the main glands of the endocrine system are shown in the diagram on the right
• the major endocrine system are shown in the diagram on the right
• the major 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 5

What is the somatic nervous system?

Answer 5

-controls muscle movement and receives information from sensory receptors

Question 6

What is the autonomic nervous system?

Answer 6

-governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses

Question 7

What is the endocrine system?

Answer 7

• one of the boys major information systems that instructs glands to release hormones directly into the blood stream
• these hormones are carried towards target organs in the body

Question 8

What is adrenaline?

Answer 8

• a hormone produced by the adrenal glands which is part of the human body immediate stress response system
• adrenaline has a strong effect on the cells of the cardiovascular system - stimulating the heart rate, contracting blood vessels and dilating air passages

Question 9

How does the endocrine and ANS work together to produce a fight or flight response?

Answer 9

• often the endocrine system and the autonomic nervous system work in parallel with one another, for instance during a stressful event
• when a stressors is perceived the thing that happens is a part of the brain called the hypothalamus triggers activity in the sympathetic branch of the autonomic nervous system
• the ANS changes from its normal resting state called the parasympathetic state to the physiologically aroused, sympathetic state
• the stress hormone adrenaline is released from the adrenal medulla into the blood stream
• adrenaline triggers physiological changes in the body which creates the physiological arousal necessary for the flight or fight response
• all of this happens in an instant as soon as the threat is detected - an acute response - and is an automatic reaction in the body
• the physiological changes associated with this sympathetic response explain why stress, panic, or even excitement, is often experienced as a sick feeling
• 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 - its actions are antagonistic to the sympathetic system
• the parasympathetic system acts as a break and reduces the activities of the body that were increased by the actions of the sympathetic branch
• this sometimes referred to as the rest and digest response

Question 10

What are the two main functions of the nervous system?

Answer 10

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

Question 11

Which sub-systems is the nervous system divided into?

Answer 11

• central nervous system
• peripheral nervous system is future sub-decided into the central nervous system
• the peripheral nervous system is further sub-divided into the autonomic nervous system and the somatic nervous system

Question 12

Which biological changes are associated with the sympathetic state?

Answer 12

• increased heart rate
• increased breathing rate
• dilated pupils
• inhibits digestion
• inhibits saliva production
• contracts rectum

Question 13

Which biological changes are associated with the parasympathetic state?

Answer 13

• decreased heart rate
• decreased breathing rate
• constricted pupils
• stimulates digestion
• stimulates saliva production
• relaxes rectum