LO5 Flashcards
what is the role of the nervous system?
the nervous system receives, transmits and responds to information from the external environment and from the body’s internal environment, through a collection of nerve cells.
what are the 5 components of the nervous system?
- the central nervous system
- spinal cord
- autonomic system
- somatic nervous system
- peripheral nervous system
what is the structure and function of the central nervous system?
the CNS is the control centre for the body.
it consists of the brain and spinal cord.
the spinal cord connects to the brain by long lines of individual nerve cells, to every area in the body.
what is the structure and function of the spinal cord?
the spinal cord is protected by specialised bones called vertebrae.
these bones have a hollow centre through which the spinal cord runs.
it transmits information to and from the brain through structures called nerves.
what is the structure and function of the autonomic system?
the autonomic system controls and regulates processes such as heart rate and gut movements (peristalsis).
these actions are automatic - unconsciously controlled.
what is the structure and function of the somatic nervous system?
sensory nerves transmit information from the senses to the brain.
motor nerves transmit information to the muscles from the brain.
the sensory and motor nerve pathways work together, for example when picking something up.
what is the structure and function of the peripheral nervous system?
all the nerves outside of the CNS make up the peripheral nervous system.
it relays information from the brain and spinal cord to the rest of the body, and the reverse information from the body to the brain and spinal cord.
peripheral nerves include autonomic, sensory and motor nerves.
what is the definition of nerves?
cells called neurones, which make up our nervous system.
nerves are specialised cells, they carry messages from one part of the body to another as tiny electrical signals.
these messages are known as nerve impulses.
what are the 10 parts of the brain?
frontal lobe
parietal lobe
limbic lobe
occipital lobe
pineal gland
medulla
cerebellum
corpus callosum
hypothalamus
pituitary gland
what is the structure and function of the cerebral cortex?
the cerebral cortex is the wrinkly, outermost layer of the brain, responsible for thinking and processing sensory information from the body.
there are 4 lobes, each responsible for processing different types of information.
it is made of tightly packed neurons.
what is the structure and function of the cerebellum?
positioned at the back of the skull.
co-ordinates and regulates muscle activity, such as walking and writing.
it is also involved in the control of muscles to maintain balance.
what is the structure and function of the frontal lobes?
carry out higher level mental processes such as thinking, decision making and planning.
what is the structure and function of the corpus callosum?
a bridge of nerve tissue that connects the 2 halves of the brain and enables communication between the two.
what is the structure and function of the hypothalamus?
responsible for the maintenance of body temperature.
it also regulates appetite and thirst.
what is the structure and function of the medulla?
automatically carries out and regulates life-sustaining functions such as breathing, swallowing and heart rate
what is the structure and function of meninges?
3 layers of membranes surrounding the brain and spinal cord.
they provide a barrier from the rest of the body and act as protection from infection.
what is the structure and function of a neuron?
neurons are specialised nerve cells that transmit electrical impulses (information) from one part of the body to another.
what are the 3 main sections of a neuron?
axon
dendron (dendrites)
myelin sheath
what is the structure and function of an axon?
axons are the long thread-like part of a nerve cell, along which impulses are conducted away from the cell body to other cells.
there is only one per neuron.
what is the structure and function of a dendron (dendrite)?
dendrons are short, branched structures on the neuron that receive electrical impulses and carry them towards the cell body.
there can be as many as 1000 per neuron.
what is the structure and function of myelin sheath?
the myelin sheath is a fatty white substance that surrounds the axon.
it forms a protective, insulating layer and enables electrical impusles to transmit quickly and efficiently along the nerve cells.
what are the 3 sections of a synapse?
pre-synaptic neuron
synaptic cleft
post-synaptic neuron
what is the function of a synapse?
to transfer electrical activity (information) from one cell to another.
how does a synapse work?
an electrical impulse travels along an axon.
this triggers the pre-synaptic neuron to release chemical messengers called neurotransmitters.
the neurotransmitters diffuse across the synapse.
they then bind with receptors on the post-synaptic membrane and then the information has been received.
what is the endocrine system?
the endocrine system is made up of glands that secrete hormones that regulate metabolism, reproduction, growth and sleep.
what are the 9 main parts of the endocrine system?
pineal gland
hypothalamus
pituitary gland
thymus gland
pancreas
ovaries
testes
adrenal gland
thyroid gland
what is the function of the pancreas in the endocrine system?
the pancreas is a gland situated near the stomach that produces insulin.
Insulin is needed to control glucose (blood sugar) levels in the body
what is the function of the pituitary gland in the endocrine system?
it is located at the base of the brain and is the master gland that regulates all the other endocrine glands.
what is the function of the adrenal gland in the endocrine system?
there are 2 adrenal glands, one situated above each kidney.
they produce adrenaline which is the fight or flight hormone.
this is released into the bloodstream as a response to a threat and prepares the body to fight or run by raising the heart and breathing rates.
what is the function of the thyroid gland in the endocrine system?
it is located in the lower front part of the neck.
the thyroid produces thyroxine, which affects growth and sustains metabolism (how the body functions)
what is the function of the reproductive glands in the endocrine system?
the ovaries and testes are the source of sex hormones.
testosterone in males affects male characteristics such as sexual development, growth of facial hair and changes at puberty, as well as sperm production.
in female, the ovaries produces oestrogen and progesterone as well as eggs. These hormones control breast growth and reproductive functions such as menstruation and pregnancy.
what are the 8 part of the kidney?
cortex
medulla
renal artery
renal vein
calyx
ureters
bladder
urethra
what is the cortex?
the outer layer of the kidney, where ultrafiltration occurs.
what is the medulla?
inner region, contains thousands of nephrons
what is the renal artery?
supplies kidney with blood from the heart. Branch directly from the aorta
what is the renal vein?
carries blood that has been filtered by the kidney
what is the calyx?
chambers through which urine passes.
it is the fibrous white region which collects urine and passes it on to the ureters
what is the ureter?
tube that carries urine from the kidney to the bladder
what is the bladder?
stores urine
what is the urethra?
urine passes out of the body through this
how do the kidneys work?
blood travels into the kidney through the renal artery.
waste products are filtered out and nutrients absorbed.
the balance of water in the body is regulated.
the renal vein takes blood away.
waste products in urine move down to the bladder.
what are the 5 main functions of the kidneys?
ultrafiltration
reabsorption
osmoregulation
removal of waste - urea
regulation of water
what is the structure and function of a nephron?
nephrons consist of a ball formed of small capillaries called a glomerulus and a small tube called a renal tubule.
the kidney nephron is a complicated twisting tube, divided into special regions that help remove poisonous wastes from the blood, as well as helping to control water, salt, pH and blood pressure levels.
there are approximately 1 million nephrons per kidney, each containing a glomerulus, bowman’s capsule, loop of henle, proximal tubule, distal tubule and collecting ducts.
what is the role of the glomerulus?
at the beginning of the nephron is the glomerulus, a network of capillaries that performs the first step of filtering blood using diffusion.
diffusion is the movement of molecules from an area of high concentration to an area of low concentration. This is allowed by the capillaries being one cell thick.
what is the role of the Bowman’s capsule?
Fluids from the blood in the glomerulus are collected in the Bowman’s capsule and further processed along the nephron to form urine. This process is known as ultrafiltration.
how does ultrafiltration occur?
The process of ultrafiltration occurs in the Bowman’s capsule.
During ultrafiltration, protein and red blood cells remain in the glomerulus. These products are not found in the urine of a healthy person.
Blood is filtered in the kidney under high pressure.
Plasma is forced out through the capillary walls into the Bowman’s capsule. This also removes waste.
The nephron peforms the job of filtration and fluid balance.
Although glucose is removed from the blood during ultrafiltration, it is always reabsorbed.
People with uncontrolled diabetes will lose glucose in urine if their blood glucose levels reach a high threshold.
how is urea removed from the body?
urea is a toxic waste product produced in the liver as a product of deamination.
deamination is the breakdown of amino acids, which are the building blocks of proteins and found in many foods. This forms ammonia, but the liver converts it to a less toxic chemical called urea.
urea passes into the blood and travels to the kidney.
it is removed through urination.
what is osmoregulation and reabsorption?
osmoregulation - water input and water output should be kept constant despite internal and external changes. It is important for all body functions that salt and water levels remain constant.
water input comes from food and drink.
water output occurs through breathing, sweating and in urination.
selective reabsorption is where the kidneys only reabsorb the products that the body needs such as water, glucose and ions.
the reabsorption of salt and glucose happens in the proximal tubule (both), and distal tubules (salts).
most water is reabsorbed in the loop of Henle.
the kidneys can conserve water levels if you are dehydrated. They can also make urine more dilute to expel excess water if necessary.
Loss of water increases the concentration of the blood, and if left uncorrected could result in our cells losing water by osmosis, as water diffuses into the plasma.
the hypothalamus in the brain detects the rise in blood concentration and it sends impulses to the pituitary gland, leading to the release of ADH.
ADH travels to target cells in the walls of the kidneys collecting ducts and all over the body.
A specialised blood supply keeps the medulla region salty, by removing salt from urine in the loop of Henle.
what is the liver?
largest internal organ
located in the upper abdomen
cleanses the blood and aids digestion by secreting bile.
what are the 3 main functions of the liver?
deamination
detoxification
production of bile
what is deamination?
the breakdown of amino acids from proteins.
our body uses part of the amino acids to make chemicals it can store like glucose and fat.
deamination results in the production of ammonia, which is a toxic waste.
ammonia is converted into urea which is a slightly less toxic chemical.
urea is transported in the blood and removed by the kidney in urine.