nervous system

• The pons connects the cerebellum to the rest of the brain and helps regulate sleep cycles.
• the nervous system has 2 main division: the central nervous system (CNS) and the peripheral nervous system (PNS)
• THE CENTRAL NERVOUS SYSTEM - receives and processes all of the information from all parts of the body. In other words, it controls the entire organ system of the body.
• The brain is the control center of the nervous system.
• brain has three main parts: the forebrain, midbrain and hindbrain. Moreover, it is divided into three main regions: the cerebrum, cerebellum and brain stem.
• cerebrum is the largest part of the brain
• hypothalamus controls the endocrine system, controls body temperature, and controls the autonomic nervous system
• cerebellum: the part of the brain at the back of the skull in vertebrates, which coordinates and regulates muscular activity.
• brain stem: controls automatic functions of the body, such as breathing and heart rate
• brain stem gas two main parts: medulla and pons
• pons: the part of the brainstem that links the medulla oblongata and the thalamus.
• medulla: the inner region of an organ or tissue, especially when it is distinct from the outer region or cortex (as in a kidney, an adrenal gland, or hair) control heat rate, respiration, and blood pressure, connects the brain to the spinal cord
• limbic system: a group of structures in the brain that are involved in emotions and memory. it has 2 main parts: the hippocampus and the amygdala
• hippocampus: the elongated ridges on the floor of each lateral ventricle of the brain, thought to be the centre of emotion, memory, and the autonomic nervous system.
• amygdala: a roughly almond-shaped mass of grey matter inside each cerebral hemisphere, involved with the experiencing of emotions. (emotional behavior)
• The spinal cord is about 40-50 cm long. Through it, the brain and the body become interconnected. composing the nerve tissues of the cord is a gray and white matter.
• The spinal cord transmits impulses all over the body to and from the brain. It is also responsible for involuntary movements.
• THE PERIPHERAL NERVOUS SYSTEM - The PNS contains all the nerves outside the brain and the spinal cord. It carries impulses from the sensory nerves to the CNS and from the CNS to the motor nerves. The PNS is further divided into two more divisions – the somatic and autonomic nervous systems.
• The Somatic Nervous System (SNS)- The SNS regulates the activities that are under conscious control. It includes all the nerves controlling the muscular system and external sensory receptors. Specifically, these receptors refer to the external sense organs – the eyes, ears, nose, skin, and tongue.
• Spinal Nerves – the nerves that carry motor and sensory signals between the spinal cord and the body.
• Cranial Nerves – the nerve fibers that carry information into and out of the brain stem
• The Autonomic Nervous System (ANS)- This is a part of the PNS which includes the motor neurons that control the internal organs. This means that the ANS regulates all activities that are considered as involuntary or those reflexes that are done without conscious will. Some of its functions include controlling the muscles in the heart and the smooth muscles in the internal organs such as the intestines, bladder and the uterus. The autonomic nervous system is further subdivided into the sympathetic and parasympathetic nervous systems.
• Sympathetic - It is known as the “fight or flight response” which controls the internal functions of the body in times of stress. In addition, it is responsible for the acceleration of heart rate, the constriction of blood vessels and the rise of blood pressure
• Parasympathetic – It is known as the “rest and digest” which is the opposite of the sympathetic nervous system. It controls the internal functions at rest. Thus, it slows down the heart rate and increases.
• cell body is in charge of the neurons activity
• dendrites receive messages from other cells
• myelin sheath insulates axon so impulse travels faster (cover the axon to protect it and help messages travel faster and easier
• axon carries message away from cell body