The Endocrine System Biopsychology

Mobilisation of energy reserves Increased blood pressure Identify two responses that result from the action of the sympathetic division of the ANS (2) Increased heart rate Pupil dilation Decreased digestion Decreased salivation Mobilisation of energy reserves Increased blood pressure Increased respiration

Briefly outline the role of the parasympathetic nervous system (2) This is part of the autonomic nervous system and the main role is to conserve energy and reduce physiological arousal such as heart rate and respirations. It can be summarised as rest and digest.

Starter Hy

The Endocrine System The endocrine system consists of structures called glands. They secrete hormones directly into the bloodstream. Regulated by the ‘master gland’ called the pituitary gland.

The Pituitary Gland The ‘master gland’ Regulates other endocrine glands Plays an important role in the stress response Examples of hormones produced ACTH (anterior) Oxytocin (posterior)

Hormones of the pituitary

Activity Gland Main Hormone Effects Testes Male characteristics Adrenal medulla Causes the fight or flight response Adrenal cortex corticosteroids Pineal Melatonin Ovaries Regulates menstrual cycle

Question Identify two hormones and briefly outline their effect (4) Adrenaline is released by the adrenal medulla (1)and causes increase in heart rate, blood pressure and inhibits digestion.(1) Oestrogen is released from the ovaries (1) and helps to regulate the female reproductive cycle (1)

Things to Remember Hormones are released by an endocrine gland and travel in the blood to their target cells. They are transported all over the body It is a much slower communication than synaptic transmission

Questions Which endocrine gland releases ACTH? What is the role of testosterone? Where is adrenaline secreted? What organ do the adrenal glands sit above? Identify an inhibitory neurotransmitter.

Starter Complete the crossword.

The Fight or Flight Response Higher brain centres SAM HPA Hypothalamus Negative feedback Anterior Pituitary Gland Sympathetic nervous system activation Adrenal cortex Corticosteroids in bloodstream Adrenal Medulla Adrenaline and noradrenaline released

What do these stress hormones do to the body? We know what adrenaline does Cortisol plays an important role in Fight or Fight as it leads to the mobilisation of fat and glucose reserves necessary for the increased activity during stress response. It provides us with a quick burst of energy. BUT

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The long term effects of stress Immunosuppression Weight gain Increased appetite Dementia Depression/anxiety Heart disease Mood swings

Question Paul does not like rollercoasters. His mouth goes dry, his heart beats faster and he sweats whilst in the queue. With reference to fight or flight, explain why his body reacts in this way (4)

Answer Paul’s sympathetic nervous system is stimulated because he sees the rollercoaster as a stressor (1) The higher brain centres perceive this threat and the hypothalamus stimulates the release of adrenaline and noradrenaline from the adrenal medulla. (1) This causes bodily arousal (1). This results in increased heart rate, sweaty palms, increased respiration and reduced salivation. This is what Paul is experiencing whilst in the queue (1).

Outline the fight or flight response (6) The fight or flight response is the bodies response to stress. The higher brain centres in the brain perceive a stressor and stimulate the hypothalamus which initially stimulates the sympathetic nervous system via the brain stem. This then stimulates the adrenal medulla to release adrenaline which causes increased heart rate and blood pressure and decreased salivation and digestion. The hypothalamus also stimulates a secondary response where the pituitary gland releases ACTH which stimulates the adrenal cortex to release corticosteroids such as cortisol. This causes the release of stored glucose, fats and amino acids and gives the body a burst of energy needed for the increased activity. This response is essential in fight or flight as it gives the body the necessary energy needed for survival.

What if I have to evaluate Fight or Flight Most research into fight and flight has been carried out on male animals. This is because there is a worry about how female hormones interfere with the fight or flight response. Therefore there is a gender bias in research into fight or flight. Taylor suggests males and females have very different fight or flight responses. Females tend to tend and befriend during stress, therefore their adrenaline increase is less pronounced than males.

What do I do if I have to evaluate Fight or Flight Research into fight or flight has practical applications. For example the more we understand the response the more we can advise people about the negative effects of stress – such as the release of cortisol being neurotoxic and reducing immune response.

What do I do if I have to evaluate Fight or Flight It can be argued that a ‘FREEZE’ response occurs first rather than fight or flight. This is clearly seen in non-human animals such as prey animals.

What do I do if I have to evaluate Fight or Flight The fight or flight response has an evolutionary basis. We would not have survived as a species without it. Therefore it is a nature explanation because the idea is that it is genetically transmitted. Those animals not having this response would not survive.