Lesson 1 Flashcards
What is the nervous system?
is a specialised network of cells in the human body and is our primary internal communication system.
What 3 mains functions does it have?
- to collect process and respond to info in the environment
- to co-ordinate the working of different organs and cells.
- relay messages from the brain to the body.
What is the central nervous system?
it comprises of the brain and the spinal cord.
the brain
- centre of all conscious awareness and is involved in all physiological processes needed for human function and survival.
- brain is made up of the cerebral cortex which is 3mm thick and covers the brain.
- is highly developed in humans and this is what separates us from animals.
- brain is divided into two hemispheres.
the spinal cord
- main function is to relay info from the brain to the rest of the body. it passes message to and from the brain and connects nerves to the PNS.
- connected to diff parts of the body through our spinal nerves which are connected to certain muscles and glands.
- enables us to perform simple reflexes.
What is the peripheral nervous system?
function of PNS is to relay nerve impulses from the CNS to the body and from the body back to the CNS.
The PNS is further divided into
- somatic nervous system - controls voluntary muscle movements and recieves info from sensory receptors.
- autonomic nervous system - governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses.
What are the divisions of the ANS?
the two main divisions of the autonomic nervous system are:
1. the sympathetic nervous system - the sns is involved in responses that help us deal with emergencies e.g. fight or flight. - nuerons from the sns travel to every organ and gland preparing the body for rapid action when an individual is under threat.
2. the parasympathetic nervous system - role of the pns is to relax the individual once the emergency has passed. it slows down the heartbeat and reduces blood pressure.
their actions are mostly antagonistic - work in the opposite direction to each other.
Sympathetic state signs: fight or flight
increased heart rate
increased breathing rate
dilated pupils
inhibits digestion
inhibits saliva production
Parasympathetic state signs: rest and digest
dec heart rate
dec breathing rate
constricts pupils
stimulates digestion
stimulates saliva production
What is the endocrine system?
consists of glands which produces hormones which are released into the blood stream to the target organs and each hormone has a specific function.
Gland - hormones - target organs - role/ effect
adrenal gland - adrenaline - liver and heart - prepares body for action - fight or flight.
ovary - oestrogen - uterus - controls puberty and the menstrual cycle in females.
ovary - progesterone - uterus - maintains the lining of the womb.
pancreas - insulin - liver - controls blood sugar levels.
pituitary gland - anti-diuretic hormone (ADH) - kidney - controls blood water level by triggering uptake of water and producing urine in kidneys.
thyroid gland - thyroxine - liver/kidneys - helps control the rate of metabolism.
testes - testosterone - male reproductive organs - controls puberty in males and production of sperm.
What is the importance of the pituitary gland?
- known as the master gland
- primary function - produces hormones and release hormones from other glands.
- controlled by the hypothalamus.
- hypothalamus uses info that is received to help regulate these functions. This involves controlling the pituitary gland.
- the pituitary gland produces hormones that travel in the blood stream to their specific target glands and stimulates these glands to produce other hormones.
How does the body prepare for fight or flight response?
- The endocrine system and ANS work together
a stressful events
