Unit 3 - Neurobiology and Communication CfE Higher Human Biology 17. Divisions of the Nervous System

Learning Intentions I can Identify the structures and functions of the nervous system I can state that the peripheral nervous system includes the autonomic and somatic nervous system I can describe the antagonistic action of the sympathetic and parasympathetic systems I can explain how the sympathetic nervous system increases heart rate I can explain how the sympathetic nervous system increases breathing rate I can explain how the sympathetic nervous system slows down digestive processes I can state that the sympathetic nervous system is involved in fight or flight I can explain how the parasympathetic nervous system decreases heart rate I can explain how the parasympathetic nervous system decreases breathing rate I can explain how the parasympathetic nervous system speeds up digestive processes I can state that the parasympathetic nervous system is involved in rest and digest

The nervous system of the human body is responsible for numerous functions, such as: analysing sensory information from the body and external environment storing some information making decisions regarding appropriate responses and behaviours. It produces motor responses by causing muscular contractions or secretion from glands. The Nervous System

The nervous system can be divided into the Central Nervous System (CNS) and the Peripheral Nervous System (PNS). The CNS is made of the brain and spinal cord. The PNS is made up of neurons throughout the rest of the body. The Nervous System

Nervous system Central Nervous System (CNS) Brain Spinal cord Peripheral Nervous System (PNS) Autonomic Nervous System (ANS) Sympathetic Parasympathetic Somatic Nervous System (SNS) The Nervous System - Overview

The PNS is comprised of sensory and motor neuron pathways which pass information to and from the CNS via electrical impulses. When a stimulus is detected by receptors in external sensory organs (e.g. eyes, ears etc) or internally (e.g. thermoreceptors in the hypothalamus), an impulse is carried along sensory nerve cells (neurons) to the CNS. This keeps the brain in touch with what is going on in the body's external and internal environments. The CNS processes the information and impulses are transmitted along motor neurons to effectors, such as muscles and endocrine glands, which bring about a response, such as muscle contraction or hormone/enzyme secretion. The Peripheral Nervous System (PNS)

Nerve impulses carried by sensory neurons Nerve impulses carried by motor neurones The Peripheral Nervous System (PNS) Receptors Effectors CNS response stimuli e.g. temperature of blood/skin external e.g. skin internal e.g. thermoreceptors e.g. muscles e.g. muscular contraction

The PNS can be divided into the Somatic Nervous System (SNS) and the Autonomic Nervous System (ANS). The somatic nervous system controls the skeletal muscles through the action of sensory and motor neurons and is involved in mostly voluntary actions, such as walking and speaking. The SNS is also responsible for involuntary reflex actions e.g. limb withdrawal. The Peripheral Nervous System (PNS) Somatic Nervous System SNS

The autonomic nervous system (ANS) is responsible for regulating internal structures such as the heart, blood vessels, bronchioles and alimentary canal. This regulation occurs through automatic, involuntary actions which involve sensory and motor neurones. The autonomic nervous system is involved in homeostatic control (e.g. regulation of body temperature or osmoregulation). The nerves of the ANS arise in the brain and emerge from the spinal cord at numerous points to reach the organs that they stimulate. The Autonomic Nervous System (ANS)

Nervous system Central Nervous System (CNS) Brain Spinal cord Peripheral Nervous System (PNS) Autonomic Nervous System (ANS) Sympathetic Parasympathetic Somatic Nervous System (SNS) The Nervous System - Overview

The ANS is made up of two parts, the sympathetic and the parasympathetic systems. The Parasympathetic System in control in times of rest and relaxation; slows functions and conserves resources acts on heart to lower heart rate slows breathing rate decreases blood flow to muscles increases blood flow to digestive system (increases digestion) Autonomic Nervous System

The Sympathetic System in control when the body is active or excited; raises activity levels acts on heart to increase heart rate increases breathing rate increases blood flow to muscles decreases blood flow to digestive system (slows digestion) increases perspiration (i.e. sweating)

The Peripheral Nervous System (PNS) The sympathetic and parasympathetic systems act on many areas of the body.

The sympathetic system is involved in the ‘fight or flight’ response, whilst the parasympathetic system is involved in the ‘rest and digest’ response. As these systems work on the same structures but have opposite effects, they are said to have an antagonistic relationship. The Peripheral Nervous System (PNS)

Questions-1 1.Describe the structures of the central nervous system 2.Describe the functions of the central nervous system 3.Describe the structures of the peripheral nervous system (PNS). 4.Describe the differences in structure between the autonomic (ANS) and somatic nervous systems (SNS)

Answers 1 1.Describe the structures of the central nervous system Brain and spinal cord 2. Describe the functions of the central nervous system The CNS processes the information sent from the senses along sensory neurons and will send out impulses along motor neurons to effectors. 3. Describe the structures of the peripheral nervous system (PNS). The PNS is comprised of sensory and motor neuron pathways 4. Describe the differences in structure between the autonomic (ANS) and somatic nervous systems (SNS) SNS involves the action of sensory and motor neurons while the nerves of the ANS arise in the brain and emerge from the spinal cord at numerous points to reach the organs that they stimulate.

Questions 2 5. Describe the functions of the peripheral nervous system (PNS). 6. Describe the differences in function between the autonomic (ANS) and somatic nervous systems (SNS) 7. Describe the functions of the sympathetic and parasympathetic system. 8. Describe the antagonistic nature of the sympathetic and parasympathetic system.

Answers 2 5. Describe the functions of the peripheral nervous system (PNS). PNS pass information to and from the CNS via electrical impulses. 6. Describe the differences in function between the autonomic (ANS) and somatic nervous systems (SNS) SNS is involved in mostly voluntary actions, such as walking and speaking. The SNS is also responsible for involuntary reflex actions. ANS is responsible for regulating internal structures such as the heart, blood vessels etc.

Answers 2 (continued) 7. Describe the functions of the sympathetic and parasympathetic system. Parasympathetic system is in control in times of rest and relaxation; slows functions and conserves resources. The sympathetic system is in control when the body is active or excited; raises activity levels 8. Describe the antagonistic nature of the sympathetic and parasympathetic system. They work on the same structures but have opposite effects