Review of Biological Approach Assumptions Genetic basis of

Review of Biological Approach Assumptions Genetic basis of behaviour Twin studies Concordance rates Genotype & Phenotype Evolutionary behaviour Strengths Weaknesses

Twin Studies adoption studies and correlation How they contribute to our understanding of the learnt innate debate

Mini-Plenary What is wrong with heritability studies? Twin studies. MZ twins reared together often treated the same. Difficult to measure the true impact of environment. DZ twins reared in the same Underestimates the environment often importance of treated differently. environment. Twins reared apart – rare – often brought up in close proximity

Biological Approach Strengths Scientific – uses experimental procedures Evidence for the nature side of nature-nurture debate Useful applications to understanding many disorders; down’s syndrome, bipolar disorder, autism.

Biological approach Weaknesses Reductionist – explains ALL behaviour in terms of genes, nerves or chemicals Over-simplistic – fails to appreciate the environment Ethical issues – genetic manipulation? Selective breeding.

5. 1 Biological Questions 1. Describe what is meant by a concordance rate. (2 marks) 2. What is the difference between a genotype and a phenotype. Give examples in your answer. (4 marks) 3. Outline theory of evolution and give examples of how it influences our behaviour. (4 marks) 4. 5. Outline one assumption of the biological approach. (2 marks) Rita and Holly are identical twins who were separated at birth. When they finally met each other at the age of 35, they were surprised at how different their personalities were. Rita is much more social and out-going than Holly. Use your knowledge of genotype and phenotype to explain this difference in their personalities. [4 marks] 6. Outline and evaluate the biological approach to explaining behaviour. (12 marks) 7. Describe one strength and one weakness of the biological approach. (4 marks)

Darwin https: //www. youtube. com/watch? v=2 d_Fkp. Vk. Qo

Sperry All that is psychological is first physiological.

6. 1 Influence of biological structures on behaviour.

Central Nervous System (CNS) The central nervous system is made up of the brain and the spinal cord. The biological approach focuses on the brain as it controls our behaviour.

Human Nervous System Draw on board functions Human Nervous System Peripheral nervous system Autonomic nervous system Sympathetic nervous system Somatic nervous system Central nervous system Brain Parasympathetic nervous system https: //www. youtube. com/watch? v=zeo 19 WVQ 47 w Spinal cord

The nervous system • Biopsychologists assume that behaviour and experiences are caused by activity in the nervous system • The nervous system is a specialised network of cells in the human body and is our primary internal communication system • It has two main functions: ü To collect, process and respond to information in the environment ü To co-ordinate the working of different organs and cells

Human nervous system Peripheral nervous system (PNS) Autonomic nervous system Somatic nervous system Sympathetic nervous system Parasympathetic nervous system Central nervous system (CNS) Brain Spinal cord The major sub-divisions of the human nervous system

The central nervous system (CNS) 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 highly developed in humans • The brain is divided in two hemispheres • The spinal cord is an extension of the brain. It is responsible for reflex actions The CNS passes messages to and from the brain and connects nerves to the PNS

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

The somatic nervous system This is the part of the PNS that is responsible for carrying sensory and motor information to and from the spinal cord

The autonomic nervous system (ANS) This governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses

The two main divisions of the ANS The two main divisions of the autonomic nervous system are: • The sympathetic nervous system • The parasympathetic nervous system Their actions are mostly antagonistic - that is they usefully work in opposition to each other

The opposing actions of the sympathetic and the parasympathetic nervous system Organ Sympathetic nervous system Parasympathetic nervous system Gut Slows digestion Increases digestion Salivary glands Inhibits saliva production Increases saliva production Heart Increases heart rate Decreases heart rate Liver Stimulates glucose production Stimulates bile production Bladder Stimulates urination (relaxes the Inhibits urination (contracting bladder) Eye Dilates pupils Constricts pupils Lungs Dilates bronchi Constricts bronchi

Generally, maintains and conserves body energy and functions Generally prepares the body to expend energy for fight or flight

Fight or flight response • Anxiety and fear are actually important for survival because they act as a mechanism to protect the body against stress and danger. • The sympathetic nervous system controls what has been called the "Fight or Flight" phenomenon because of its control over the necessary bodily changes needed when we are faced with a situation where we may need to defend ourselves or escape.

Imagine… • You are walking down a dark street at night by yourself. Suddenly you hear what you suspect are footsteps approaching you rapidly. • What happens? • Your sympathetic nervous system kicks in and in an instant, your body is prepares itself for either defence or escape.

Fight or flight? • These changes enable the body to take action and protect itself in dangerous situations, either by running away or fighting – hence, the fight or flight response.

When the ‘threat’ has passed… • Now imagine that the footsteps belong to a good friend who catches up to you and offers to walk you home. You feel relief instantly, but your body takes longer to adjust. • In order to return everything to normal, the parasympathetic nervous system kicks in. • This system is slow acting, unlike its counterpart, and may take several minutes or even longer to get your body back to where it was before the scare.

• These two subsystems are at work constantly shifting your body to more prepared states and more relaxed states. • Every time a potentially threatening experience occurs (e. g. , someone slams on their breaks in front of you, you hear a noise in your house at night, you hear a loud bang, a stranger taps you on the shoulder unexpectedly), your body reacts.

The constant shifting between these two systems keeps your body ready for your current situation.

6. 2 Structure and Function of Neurons “Our deepest emotions are nothing more than chemical equations” Bullet with Butterfly Wings (Smashing Pumpkins)

Neurons

Facts about Neurons … • 100 billion neurons or nerve cells in the human nervous system. • Some are small and some are over 1 metre long. • Neurons are nerve cells that transmit nerve signals to and from the brain at up to 200 mph. • A typical neuron has about 1, 000 to 10, 000 synapses (that is, it communicates with 1, 000 -10, 000 other neurons, muscle cells, glands, etc. )

The Structure of Neurons

Neurons Source: science photo library Neuronal cell bodies Axons Synapses occur at the junctions

Motor Neuron Carry messages away from the brain and spinal cord to the organs and muscles in the body. CNS - PNS

Sensory Neuron Carry messages from the receptors in the body to the brain and spinal cord. PNS - CNS

Interconnecting/Relay Neuron Transmits information from sensory neurons to motor neurons

Synapses The gap between the end of one neuron and the dendrites of the next neuron.

Types of Neuron • Use page 228 in your textbook to complete the blanks on the sheet.

Structure Function Axon The axon is the elongated fibre that extends from the cell body to the terminal endings carries the nerve impulse away. The larger the axon, the faster it transmits information. Myelin sheath Insulating layer – (fatty substance ) which increases speed of transmission. Axon Terminal The terminal buttons are located at the end of the neuron and are responsible for sending the signal on to other neurons. Dendrite are tree-like extensions at the beginning of a neuron Large surface area covered with synapses. Receive information from other neurons and transmit electrical stimulation to the soma. Synapse At the end of the terminal button is a gap known as a synapse. Neurotransmitters are used to carry the signal across the synapse to other neurons. Node of Ranvier gaps between the myelin sheaths generated by different cells. At nodes of Ranvier, the axon is uninsulated and therefore capable of generating electrical activity. Schwann Cells Wrap around the Axon to form the myelin sheath

Activity: Reflex Arc Construct a neural pathway for being hit on the knee with a hammer! Hammer Sensory Neuron Knee Interconnecting Neuron Motor Neuron

Synaptic Transmission • Synaptic Transmission: the process by which nerve impulses are carried across the small gap, the synapse, between one neuron and another. The nerve impulse is an electrical signal which is carried by chemicals called neurotransmitters. • This happens at very high speed e. g. visual information seems to be encoded within 50100 milliseconds of neuronal activity.

Synapses • Neurons transmit signals electrically along their axons • The synapses (junctions between neurones) transmit signals chemically.

Synapse Source: neuroscience. wustl. edu Vesicles filled with neurotransmitter Synaptic cleft Location of receptors (postsynaptic density)

Vesicles release neurotransmitter into synaptic cleft

Neurotransmitter binds to receptors & activates them

Excess neurotransmitter is taken up by the pre-synaptic neurone

Enzymes are released to break down the remaining neurotransmitter

Vesicles are replenished with new & reused neurotransmitter

What Does It Look Like?

Let’s Synapse! • Each person in your group has a label that identifies which part of the process of synaptic transmission you are. • Your group must order themselves in such a way that will demonstrate the process of synaptic transmission.

Excitatory or Inhibitory • Excitatory potentials: increases the chance of the neuron firing. • Inhibitory potentials: decreases the chance of a neuron firing.

Neurotransmitters Information is carried by biochemical substances called neurotransmitters. The terminal buttons and the dendrites of other neurons do not touch, but instead pass the information containing neurotransmitters through a Synapse. http: //www. youtube. com/watch? v=_chkzzv. Fvo. Q http: //www. youtube. com/watch? v=90 cj 4 NX 87 Yk&feature=related

Neurotransmitters A chemical passed from one neuron to another which either excites or inhibits the cell . Excitatory synapses –make next nerve likely to fire Inhibitory synapses make next nerve less likely to fire

6. 3 Neurochemistry

The Endocrine System https: //www. youtube. com/watch? v=HXPCQBD_WGI

The Endocrine System • The endocrine system is in charge of body processes that happen slowly, such as cell growth. • Faster processes like breathing and body movement are controlled by the nervous system. • However, even though the nervous system and endocrine system are separate systems, they often work together to help the body function properly.

These release adrenalin directly into the bloodstream which prepares the body for fight or flight by constricting blood vessels in the stomach. This inhibits digestion and gives you that sick feeling as well as increasing your heart rate This controls the release of hormones from all other endocrine glands This facilitates the release of the female hormones – oestrogen and progesterone This facilitates the release of the male hormones – testosterone

Summary questions • Using an example, explain what is meant by the fight or flight response If you hear a noise that makes you jump, your body immediately diverts blood away from your stomach to your muscles in order for you to stay and confront a potential attacker (fight), or run away (flight)

Summary questions • Give two actions of the sympathetic nervous system and two actions of the parasympathetic nervous system • Sympathetic nervous system – dilates pupils, inhibits saliva production, dilates bronchi, speeds up heart rate, inhibits digestion, stimulates glucose production, inhibits urination • Parasympathetic nervous system – constricts pupils, stimulates saliva production, constricts bronchi, slows down heart rate, stimulates digestion, stimulates bile production, stimulates urination

Summary questions • Billy is an A level student. He has been asked by his teacher to give a short presentation to the other psychology students in his class. Just before his presentation, Billy feels his mouth go dry and he starts to sweat. After the presentation has ended, Billy feels his breathing slow down and he begins to feel thirsty. • Use your knowledge of the autonomic nervous system to explain Billy’s behaviour before and after the presentation.

Possible answer Billy feels stressed about giving a presentation to the class and this activates sympathetic responses in his autonomic nervous system. Blood is diverted to the muscles for energy and as a result, Billy sweats to allow heat energy to be lost from the surface of the skin. It is the body’s cooling mechanism. His salivary glands have inhibited saliva production making his mouth go dry. Once the presentation is over, Billy’s stress is no longer present and his parasympathetic nervous system is now acting to restore his bodily functions to a normal state; this is why his breathing is slowing down. He feels thirsty as his previously inhibited saliva production has dried his mouth out and now he is aware of this and this needs rectifying

The Endocrine System Composed of a number of glands that release hormones. Hormones travel through the bloodstream and affect different body organs. Endocrine system provides an additional means of communication in the nervous system. The pituitary gland – ‘the Master Gland’ which controls other glands – it is located deep in the middle of the brain in the hypothalamus. The most important gland psychologically is the adrenal gland - adrenaline – the stress hormone. When the brain perceives an event as stressful the Brain stimulates the sympathetic nervous system which instructs the adrenal gland to release the hormone adrenaline.

6. 4 Fight or Flight Response Walter Cannon (1932) idea of flight or fight response provides a relationship between arousal and stress. ‘response to a stressor that results in a state of physiological arousal so that the individual is prepared to take flight or fight”

Fight or Flight http: //www. youtube. com/watch? v=J 968 Wco 1 u 0 s&feature=related http: //www. youtube. com/watch? v=V 08 d. Wz 5 XNBA&feature=related http: //www. youtube. com/watch? v=4 g 25 d 7_Afmc&feature=related http: //www. youtube. com/watch? v=ZEh. PIx. Oxku. Y&feature=related

Activity: Draw two bodies on two separate pages. Annotate A) The ANS and Endocrine Response B) The Sympathetic and Parasympathetic Response.

Central Nervous System

The effects of stress: Fight or Flight

Central Nervous System

Stress and the nervous system Cerebral Cortex – sends signals to Hypothalamus – coordinates homeostasis and stress response Sends message down the ANS – sympathetic nervous system

Discussion Human stress mechanisms have not evolved to cope with modern society. The mechanisms are more damaging to health than helpful. Many stress situations are not life threatening – so why do we have a flight or fight response?

Plenary • • Key Points ANS – involuntary Sympathetic – fight or flight Parasympathetic – rest and digest Endocrine system works in conjunction with the sympathetic nervous system.

Quiz • Write down five quiz questions and the answers. • Quiz your partner. • Swap your questions and find a new partner.