The Nervous system and the Endocrine system Flashcards
What is the Nervous system?
- Specialised network of cells (primal internal communication system), based on electrical and chemical signals
- Consists of two subsystems: central nervous system, peripheral nervous system
What are the two main functions of the nervous system?
- Collects, processes and responds to information in the environment
- To co-ordinate the working of different organs and cells in the body
What is the Central Nervous system?
- Brain and Spinal cord
- Brain ‘centre of all awareness’ cerebral cortex is 3mm thick and highly developed in humans
- spinal cord is an extension of the brain, passes messages to and from the brain, connects nerves to the PNS. Responsible for reflex actions
What is the Peripheral Nervous system?
- Transfers messages via neurons to and from CNS
- Further divided into: Autonomic Nervous system - governs vital functions e.g breathing, heart rate, digestion, sexual arousal and stress responses and Somatic Nervous system - governs muscle movement and receives info from sensory receptors
How does the Endocrine system work?
- Glands e.g Thyroid produce hormones e.g thyroxine that are secreted into bloodstream and effects cells with a receptor for said hormone.
- most hormones affect multiple organs e.g thyroxine increases heartrate and affects metabolic rate
- Pituitary gland = master gland (controls release of hormones from all other endocrine glands in the body)
How are Endocrine system and Autonomic Nervous system linked?
- e.g during a stressful event: when a stressor is perceived the hypothalamus activates pituitary gland which triggers activity in the sympathetic branch of the AMS
- ANS changes from parasympathetic state to physiologically aroused sympathetic state
How does Fight of flight occur/ what are the features?
Adrenaline: released from the adrenal medulla into bloodstream. Adrenaline triggers physiological changes which creates physiological arousal necessary for flight/fight
Immediate and Automatic: as soon as the threat is detected, an acute response and an automatic reaction
Parasympathetic action: once threat has passed parasympathetic branch of the ANS works in opposition to the sympathetic nervous system. Acts as a break to fight/flight activities - rest and digest response
What does the Sympathetic state do?
- Increases heart rate, breathing rate, dilates pupils, inhibits digestion, inhibits saliva production, contracts rectum
What does the Parasympathetic state do?
- decreases heart rate, breathing rate, constricts pupils, stimulates digestion, stimulates saliva production, relaxes rectum