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Animal Responses Notes

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Animal responses Context In animals, responding to changes in the environment is a complex and continuous process, involving nervous, hormonal and muscular co-ordination. Candidates should be able to:

Discuss why animals need to respond to their environment;
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To escape predators To control Temperature To find and stay in suitable habitats To respond to frightening/stressful stimuli Maximize chances of survival to pass on their genes

Outline the organization of the nervous system in terms of central and peripheral systems in humans; The nervous system can be divided into the central nervous system and the peripheral nervous system.
- The CNS is made up of the brain and spinal cord.
- The peripheral nervous system consists of nerves, which run between the CNS and the rest of the body - from receptors and to effectors. The peripheral nervous system has two components:
- The somatic nervous system, which includes all sensory neurones and also the motor neurones that run to skeletal muscles.
- The autonomic nervous system, which consists of two sets of motor neurones carrying impulses to effectors other than the skeletal muscles, such as glands and the muscles of the guy and heart. Neurones of the sympathetic nervous system and parasympathetic nervous system use different neurotransmitters and so have different, often antagonistic, effects.

Outline the organization and roles of the autonomic nervous system; The autonomic nervous system carries action potentials to all of the internal organs - sometimes called the viscera. It controls the activity of allthe smooth muscle in the body - for example, in the walls of arterioles and in the wall of the alimentary canal. It also controls the rate of beating of the cardiac muscle in the heart and the activities of exocrine glands such as the salivary glands. 'Autonomic' means 'self-minding' and this refers to the fact that most of the activities that are controlled by the autonomic nervous system are not usually under our voluntary control.

The autonomic nervous system is divided into two nervous systems:

1) The Sympathetic Nervous system - Fight or Flight a. The neurotransmitter which carries most impulses across synapses of the sympathetic nervous system in noradrenaline, which is very similar to adrenaline. b. The effect of impulses arriving at organs via the sympathetic nervous system is to stimulate them. c. For example, the heart might beat faster, the pupils might dilate etc. d. Some neurones in the sympathetic system use acetylcholine as the neurotransmitter that carries impulses to effector organs. E.g. The sweat glands, the erector muscles in the skin, and some blood vessels. The effects are still mostly stimulatory. e. As well as the direct activationof various target organs, the sympathetic nerves supplying the adrenal glands cause these glands to secrete the hormones adrenaline and noradrenaline into the blood. Between them, the sympathetic nervous system and these hormones bring about a range of responses, e.g.: i. Increased Heart rate ii. Widening of pupils iii. Relaxation of sphincter muscle- causing urination 2) The parasympathetic nervous system - Rest and Digest a. The neurotransmitter is acetylcholine b. Pupils constrict/ heart rate slows

Describe, with the aid of diagrams, the gross structure of the human brain, and outline the functions of the cerebrum, cerebellum, medulla oblongata and hypothalamus;

The brain is surrounded and protected by the bones of the cranium and also by the three membranes known as meninges. These membranes help to secrete cerebro-spinal fluid, which provides protection and cushioning of the

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