endocrine system + nervous system + reflex arc - 2 Flashcards
what does the endocrine system do?
regulates mood, metabolism, tissue function, growth and developement, and reproductive processes
what is this system made up of?
glands that secrete hormones directly into the bloodstream
hormones
chemical messengers that target a specific group of cells, in order to do some actvity or to stop doing an activity
- they act by binding to chemical receptors on specific levels called target cells
- they are proteins with specific shapes that match the receptors on their target cells
- they may not be produced until specific times in a person’s life
hormones communicate with cells by:
- heading towards their target cell in the blood stream to bring about a particular change or effect to that cell.
- binding with specific protein receptors inside or on the surface of the cell and specifically changing the cell’s activities
glands
structures that produce hormones (chemicals that serve as messengers for the endocrine system to maintain homeostasis)
hypothalamus
both systems use it to sense, regulate, and process change in the body and restore them to normal through feedback loops
The Glands of the Endocrine System
- hypothalamus
- pituitary gland
- thyriod gland
- parathyroids
- adrenal glands
- pancreas
- ovary
- testis
Pituitary gland
- the master gland because it affects mult. organs in th ebody
- it is a bean sized organ found at the base of the brain
- secretes hormones that regulate many body functions & controls the cation of other endocrine glands by actuvating them or turning them off
Hypothalamus
- found next to the pituitary gland
- it links the nervous system and the endocrine system
- it controls the secretions of the pituitary gland & recieves internl sensory information
- the activity level of the hypothalamus depends by the levels of hormones alr present in the blood
- it secretes a hormone that will trigger and activate the pituitary gland to secrete other hormones that have effects all over the body
Adrenal Glands
- pyramid shaped structures, found on top of the kidneys
- they’re glands that help the body recover from stress and respond to emergencies by secreting several different hormones
- aldosterone is a hormone that inhibits the amount of sodium excreted in urine and serves to maintain blood volume and pressure
- the hormone cortisol aids in the metabolism of fats, proteins, and carbohydrates
- the hormones epinephrine plays a role in the body’s response to stress
thyroid glands
- base of the neck
- play a major role in regulating the body’s metabolism, which can impact weight
- produces hormones that regulate metabolism, body heat, and bne growth
parathyroid glands
4 small glands that release hormones that regulate the calcium levels in the body which can impact bone density
pancreas
works in the digestive system as a gland that produces digestive enzymes ancd in the endocrine system a sa gland that produces the hormone, insulin and glucagon
insulin
the hormone which regulates teh amount of glucose in the blood
glucagon
promotes the breakdown of glycogen to glucose in the liver
the hormones that help regulate blood glucose levels
insulin and glucagon
blood glucose
amount of sugar in the blood;
normal level: 80-120 mg in 100ml of blood
what does the thyroid produce?
thyroxine
what does thyroxine do?
regulates the way cells reease energy from nutrients
People who produce too much thyroxine will experience what symptoms?
nervousness, weight loss, increased thirst, rapid heartbeat, and an intolerance for heat
how does teh body react when your thyroid is overactive?
the pituitary senses this and slows or shuts down the production of TSH
how does teh body react to when you have a low thyroid hormone amount?
the pituitary releases thyroid stimulating hormone to signal the thyroid to release more thyroid hormone
neurons
cells inside the brain, are electrically active chemical factories that carry messages to and from the brain and body, and within our brain
- All the neurons you will ever have are present at birth
- they don’t divide to make new cells
- they grow and make connections within our brains as we age
- the more connections we have, the better
glial cells
support and feed the neurons, packed around them
macrophage
clears up dead cells and kills germs
signals that pass through neurons
they result in our sensations, thoughts, movements, memories, and feelings
Neurons are made up of 4 parts:
- dendrites
- the cell body
- axon
- axon terminal
the cell body
- contains the nucleus, where most of the molecules that the neuron needs to survive and function are made and where neurotransmitters are made
neurotransmitters
chemical messengers which help messages travel from neuron to neuron
Path of signals through the neuron
dendrites –> (through) cell body –> (down) axon (covered in myelin) –> signal stimulates sacs, which release neurotransmitters –> (into) the synapse
dendrites
- extend out from the cell body and recieve messages from other nerve cells (look like branches).
- recieve stimulus and then send an electrical signal towards the cell body
axon
Gets messages to where they’re needed
messages will travel at different speeds down it. If it has had other cells wrapped around it to form a sheath, then the messages will travel much faster.
- part of the neuron that moves an electrical signal from the cell body to the end of the neuron, the axon terminal
- there, it communicates w/ other neurons, muscles, or glands
sheath
made up of a fatty molecule called myelin, which increases speed of transmission
chemical activity only occurs when there’s no fat along the axon, causing it to travel faster
Axon Terminal
- part of th eneuron where neurotransmitters are released into the empty space between neurons (synapse)
- These chemicals send the impulse to the next neuron, muscle, or gland
synapse
the place where a signal passes from one neuron to the next
- neurotransmitters cross it and attatch to a neighboring cell, and the process continues until it reaches where it’s being sent
- electrical signals called action potentials are translated into chemical signals called neurotransmitters that cross the gap
The Nervous System has two systems:
- Central Nervous System
- Peripheral Nervous System
CNS
- brain + spinal cord
- interprets sensory info to make decisions
PNS
- sensory neurons + motor neurons in bundles
- neurons that project between the CNS out of the spinal cord connect the nervous system to the rest of the body
neurons that form the reflex arc
sensory neurons, interneurons, motor neurons
what is a reflex arc?
neural pathways that reflexes occur over
sensory receptor
reacts to stimuli
effector organ
muscle or gland that reacts
Interneurons
- recieve signal
- send to CNS
- relay to motor
Motor
carry nerve impulses from the brain or spinal cord to muscles and glands to carry out a specific task
Neurons
- cells that pass electrical and chemical signals along pathways in the bran and body
- when neurons are signaled by the brain, they send action potentials to message other cells, continue transmitting a signal, or release neurotransmitters
- info from one neuron flows to another neuron across a small gap called a synapse
Path of Action Potential
Dendrites –> Cell Body –> Axon –> Axon Terminal
Path of Action Potential Detailed
- Signal recieved at Dendrites
- Travels through the cell body
- Continues down the axon (moves quickly because of myelin sheath)
- Reaches the axon terminal & releases a neurotransmitter into the synapse
recieve and relay to multiple cells
Neural Pathway
- stimulus
- Dendrite (skin)
- sensory neuron
- interneuron
- part of brain (hypothalamus)
- motor neuron
- receptor
- movement (result)
4 lobes of the brain
- frontal lobe (reasoning, motor control, emotion, and language)
- parietal lobe (integrating sensory information, including touch, temperature, pressure and pain.)
- temporal lobe (processing affect/emotions, language, and certain aspects of visual perception)
- occipital lobe (visual perception, including colour, form and motion)
