Nervous system Flashcards
Nervous system
Consists of the central nervous system (CNS) and peripheral nervous system (PNS)
Functions of NS
Collect, process and respond to information in the environment.
Co-ordinate the working of different organs and cells in the body.
What is Nervous system subdivided into?
Central NS
Peripheral NS
Central NS
consists of the brain and spinal cord and is the origin of all complex commands and decisions. It passes messages to and from the brain and connects the nerves to the PNS
Peripheral Nervous System
Transmits messages via neurones to and from the CNS. Subdivided into the ANS and SNS
Autonomic Nervous System (ANS)
Involuntary . Governs vital functions in the body such as breathing, heart rate, digestions, sexual arousal and stress responses.
Somatic Nervous System (SNS)
Controls muscle movement and receives information from the sensory receptors.
ANS has two divisions known as sympathetic and parasympathetic. What do they do
Sympathetic state: Parasympathetic:
Increases HR Decreases HR
Increases Breathing rate Decreases Breathing rate
Dilates pupils constricts pupil
Inhibits digestion Stimulates digestion
Inhibits saliva production Stimulates Saliva prod
Contracts rectum Relaxes rectum
Endocrine system
instructs glands to be released directly into the blood stream. These hormones are carried towards target organs in the body. They regulate bodily functions
Hormones
Chemical messengers that travel in the bloodstream and only affect target organs.
Example of Hormone
Thyroxine:
Produced by thyroid gland
Increases HR
and metabolic rate
Affects growth
Pituitary gland
located in the brain and is referred to as the master gland because it controls the release of hormones from other endocrine glands
Fight or Flight
Hypothalamus triggers activity in the sympathetic branch of ANS. ANS changes body from parasympathetic state to sympathetic state. Adrenaline is then released from adrenal gland which triggers the physiological changes in the body
Adrenaline
Produced by adrenal glands and is the body’ immediate stress response system. It increases HR, contracts Blood vessels and dilates air passages
