Cerebrum The adult brain has six major regions. The cerebrum is the largest region, controlling conscious thought, complex movements, and memory.
The Brain Stem The brain stem directly attaches the brain to the spinal cord. The neurons responsible for controlling breathing . Controls heart rate, blood pressure, swallowing, and breathing
Cerebellum The cerebellum coordinates posture, balance, and body movements.
Protection of the CNS The first layer of protection are the flat bones of the skull. Below the bone are the meninges, membranes of connective tissue. Dura mater is the outermost thickest layer. Arachnoid mater is a network of blood vessels. Pia mater is the innermost layer.
The brain and the spinal cord are protected by 3 membranes, called meninges.
Function of the spinal cord, page 82 It connects the brain to the PNS. It transmits nerve impulses and control many reflex actions.
The autonomic nervous system, page 83. Work with the image:
Responses of the somatic nervous system, page 84
Voluntary response
Involuntary response, automatic reflex actions originate in the spinal cord
Reflexes A reflex is a rapid, involuntary response to a stimulus. These actions occur more quickly because they occur over a reflex arc, a pathway that bypasses the brain.
The Reflex Arc A reflex arc begins with a stimulus at a sensory neuron, such as pain or heat. The sensory neuron is depolarized, and the signal is sent through its axon.
The signal is processed by an interneuron in the spinal cord, which then activates a motor neuron.
A neurotransmitter is released at a cholinergic synapse. The muscle contracts in response to the neurotransmitter, and the reflex is complete.
Page 82- Cross section of the cerebrum and spinal cord, 2 types of tissues White matter, composed of myelin-covered axons Grey matter is made up of neuron cell bodies, axons without myelin and dendrites
What are the differences in the distribution of the grey matter in the cerebrum and the spinal cord? In the spinal cord the grey matter is shaped like a butterfly´s wings and is found in the centre. In the cerebrum the grey matter is found in the outer area
Layers of the Cerebrum The cerebrum has two layers: Outer grey matter that contains neuron cell bodies. Inner white matter that contains axons encased in myelin sheaths.
Question 2, page 82
Activities page 83
Question 7 page 83
Activities Page 85