F Animal Responses By Ms Cullen

The Brain It is made up of white matter on the inside and grey matter (mainly cell bodies) in the outer cortex. It is made up of white matter on the inside and grey matter (mainly cell bodies) in the outer cortex. The cavities which exist in the spinal cord extend into the brain and are filled with cerebro-spinal fluid. The cavities which exist in the spinal cord extend into the brain and are filled with cerebro-spinal fluid. It is poorly understood in detail, though some areas and functions are known. It is poorly understood in detail, though some areas and functions are known.

The Brain

Week 28 (a) The left cerebral cortex labelled to show locations of some of the sensory and motor areas; (b) there is a relationship between the size of motor area in the brain and the complexity of movements (a ) (b)

The Brain Can receive sensory information from various sources, compare it with previous experience and initiate appropriate responses. Can receive sensory information from various sources, compare it with previous experience and initiate appropriate responses. Three distinct sections – forebrain (cerebrum), midbrain and hindbrain (cerebellum & medulla oblongata). Three distinct sections – forebrain (cerebrum), midbrain and hindbrain (cerebellum & medulla oblongata). The forebrain is the largest. The forebrain is the largest. Surrounded by the meninges & protected by the skull. Surrounded by the meninges & protected by the skull.

The Brain; Medulla Oblongata Controls many vital reflex actions such as heart rate, breathing rate & blood pressure. Controls many vital reflex actions such as heart rate, breathing rate & blood pressure. The VAGUS NERVE attaches here. The VAGUS NERVE attaches here. It is a link between the brain and the spinal cord. It is a link between the brain and the spinal cord. Also controls other reflex actions such as coughing, sneezing & salivation. Also controls other reflex actions such as coughing, sneezing & salivation.

The Brain; Cerebellum Coordinates movement & posture (receives sensory information from muscles and the inner ear). Coordinates movement & posture (receives sensory information from muscles and the inner ear). It can control learned activities; riding a bike, walking etc… It can control learned activities; riding a bike, walking etc…

The Brain; Hypothalamus Found below the Thalamus at the base of the forebrain. Found below the Thalamus at the base of the forebrain. Is a control centre for the AUTONOMIC NERVOUS SYSTEM. Is a control centre for the AUTONOMIC NERVOUS SYSTEM. Controls such things as thirst, hunger and thermoregulation by monitoring the blood that passes through it. Controls such things as thirst, hunger and thermoregulation by monitoring the blood that passes through it. Has a strong influence on the PITUITARY GLAND, which has a major role in influencing other endocrine glands. Has a strong influence on the PITUITARY GLAND, which has a major role in influencing other endocrine glands.

The Brain; Cerebral Hemispheres Receive sensory information, cross-reference it with previous experience and initiate the correct motor responses. Receive sensory information, cross-reference it with previous experience and initiate the correct motor responses. This allows coordination of all the voluntary actions of the body; learning, reasoning, intelligence, personality and memory. This allows coordination of all the voluntary actions of the body; learning, reasoning, intelligence, personality and memory. Emotions are processed in the forebrain area with taste, vision, hearing, smell and touch all processed in other areas. Emotions are processed in the forebrain area with taste, vision, hearing, smell and touch all processed in other areas.

The brain; functions Compose a table to describe the functions of each of these regions. Compose a table to describe the functions of each of these regions. MedullaCerebellumHypothalamusCerebralHemispheres

Week 28 The human brain shown in cross-section within the skull

3d/index.html 3d/index.html Use the website above to explore the brain, it’s structure and function more thoroughly. Use the website above to explore the brain, it’s structure and function more thoroughly.

The human nervous system

CNS & PNS The central nervous system is made up of the brain and the spinal cord. The central nervous system is made up of the brain and the spinal cord. The peripheral nervous system is composed of paired nerves, which take information to and from the CNS. The peripheral nervous system is composed of paired nerves, which take information to and from the CNS. Control and coordination by the nervous system occurs by detecting stimuli, processing this information and initiating responses to it. Control and coordination by the nervous system occurs by detecting stimuli, processing this information and initiating responses to it.

Week 28 The cranial and spinal nerves of the peripheral nervous system

Neurones Highly specialised cells with the ability to transmit impulses and form a grid of nervous pathways throughout the body. Highly specialised cells with the ability to transmit impulses and form a grid of nervous pathways throughout the body. The nervous system contains sensory neurones, relay (inter) neurones and motor (effector) neurones. The nervous system contains sensory neurones, relay (inter) neurones and motor (effector) neurones.

Comparison of sensory & motor neurones

Neurone components Dendrites Dendrites Cell body Cell body Axon Axon Schwann cells/Nodes of Ranvier Schwann cells/Nodes of Ranvier Myelin sheath Myelin sheath Axon terminal Axon terminal Synaptic end bulb Synaptic end bulb

How is the Nervous System Organised? Week 28

How is the Motor System Organised? Somatic Motor neurones carry impulses from CNS to skeletal muscles (under voluntary control). Motor neurones carry impulses from CNS to skeletal muscles (under voluntary control).Autonomic Motor neurones carry impulses from the CNS to smooth muscles (which are not under voluntary control). Motor neurones carry impulses from the CNS to smooth muscles (which are not under voluntary control).

The Autonomic Nervous System ‘self-governing’

The Role of The Autonomic Nervous System Controls most homeostatic mechanisms in the body. Controls most homeostatic mechanisms in the body. Controls all smooth muscle eg in walls of gut and arterioles. Controls all smooth muscle eg in walls of gut and arterioles. Controls the rate of the beating of cardiac muscle. Controls the rate of the beating of cardiac muscle. Controls secretion from exocrine glands eg salivary amylase. Controls secretion from exocrine glands eg salivary amylase. Most of activities controlled by autonomic nervous system are beyond our voluntary control. Most of activities controlled by autonomic nervous system are beyond our voluntary control.

The Structure of The Autonomic Nervous System Majority of autonomic neurones are non- myelinated (compared to somatic neurones which are myelinated). Majority of autonomic neurones are non- myelinated (compared to somatic neurones which are myelinated). In autonomic system at least 2 neurones are connected to effector (only 1 neurone in somatic). In autonomic system at least 2 neurones are connected to effector (only 1 neurone in somatic). These 2 neurones connect to a swelling called a ganglion. These 2 neurones connect to a swelling called a ganglion. There are 2 types of motor neurones: sympathetic and parasympathetic. There are 2 types of motor neurones: sympathetic and parasympathetic.

Parasympathetic – ‘rest & digest’ Most active when asleep or relaxing. Most active when asleep or relaxing. Nerve pathways all begin in brain, top of spinal cord or very base of spinal cord. Nerve pathways all begin in brain, top of spinal cord or very base of spinal cord. Neurones carry impulses out of brain all the way to the wall of the organ it will effect, so they can be very long. Neurones carry impulses out of brain all the way to the wall of the organ it will effect, so they can be very long. The neurotransmitter released into the organs is acetylcholine. The neurotransmitter released into the organs is acetylcholine. Effects: decreased heart rate, pupils constrict, decreased ventilation rate, sexual arousal. Effects: decreased heart rate, pupils constrict, decreased ventilation rate, sexual arousal.

Sympathetic – ‘fight or flight’ Most active when stressed. Most active when stressed. The axons of the pre-ganglionic neurones pass out of spinal cord and connect with the motor neurone cell bodies in these ganglia. The axons of the pre-ganglionic neurones pass out of spinal cord and connect with the motor neurone cell bodies in these ganglia. Neurones carry impulses to a ganglion just outside the CNS so they are very short. Neurones carry impulses to a ganglion just outside the CNS so they are very short. The neurotransmitter released into the organs is noradrenaline. The neurotransmitter released into the organs is noradrenaline. Effects: increases heart rate, pupils dilate, breathing rate increases, liver releases glucose, increased sweating, orgasm. Effects: increases heart rate, pupils dilate, breathing rate increases, liver releases glucose, increased sweating, orgasm.

Week 28 The autonomic nervous system showing sympathetic and parasympathetic divisions

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