The BRAIN 🧠Flashcards
What are the 3 parts the brain is divided into?
- The forebrain
- The mid brain
- The hind brain
What parts make up the forebrain ?
The cerebrum and the hypothalamus
What is the cerebrum?
The cerebrum is divided into two hemispheres the left and the right. It is divided k to 4 lobes.
What is the left and right hemisphere responsible for?
The left hemisphere is for verbal aspects, while the right is artistic.
What are the cerebrum 4 lobes and what are they responsible for?
- Frontal lobe- higher mental activities, personality, memory
- Parietal lobe- the 3 Ts ( tastes, touch, temperature)
- Occipital- sight
- Temporal- hearing
What is the hypothalamus?
-maintain s homeostasis
-régulâtes h20 levels, urine levels, thirst
- produces hormones (GnRH)
Controls ptuitsry glands
What is the midbrain responsible for?
This is the connection between the fore and hindbrain
What is the hindbrain?
AKA the brain stem, this consists of the medula oblongata, the pons, and the cerebellum
What is the medulla oblongata?
Controls the autonomic system, (involuntary)
What does the pons do?
The pons acts as a bridge between the cerebrum, cerebellum, and the medula
What does the cerebellum do?
Responsible for muscle movement, coordination, tone, and balance.
What are the 3 layers of the eye?
- the sclera (the front layer)
- the corroid (mid layer)
- the retina (the last layer)
What is the sclera?
The sclera protects it as well as maintains its shape.
This contains the cornea, which bends light to the retina It acts as the window to the eye
What is the choroid layer?
This is the mid layer, and contains many blood vessels which provide O2, and nutrients. It is very pigmented (black) in order to absorb light
What is the retina?
The retina is the last layer, and is where the light is directed. It also has photoreceptors and the fovea centralis
What is the iris?
A coloured muscle which controls the size of the pupil
What is the pupil?
A hole which changes the amount of light allowed into the eye
What is the lens?
The lens is behind the pupil and focuses the light onto the retina. It is very flexible, and is controlled by ciliary muscles.
What is the vitreous humour?
fluid filled sac, maintains shape and light passes through
What are the two types of photoreceptors?
There are rods- used for dim light
and cones- used to see colour (red, yellow, blue)
What is the fovea centralis?
A part of the retina, where all the light is focused. There is a high concentration of cones surrounded by rods here.
What is the optic nerve?
Composed of sensory neurons (sight), and sends info to occipital lobe
What is the order of how we see?
- Light goes into cornea,
- cornea bends light towards pupil
- pupil controls amount of light towards lens
- Lens focuses light
- retina (fovea centralis)
- photoreceptors triggered
- Info sent from optic nerve to brain
- Info received in occipital lobe
What are the 3 sections the ear is divided into?
- outer ear
- middle ear
- inner eat
What is the outer ear?
It collects sound waves,
and contains the pinna, and the auditory canal
What is the pinna?
This funnels sound into the ear, is the outside part of ear
What is the auditory canal?
Funnels sound to the tympanic membrane (eardrum)
What is the middle ear?
This converts sound waves into mechanical vibrations
Contains the tympanic membrane and the ossicles
What is the tympanic membrane?
AKA the eardrum, converts soundwaves to mechanical vibrations
What are the ossicles?
3 bones, amplify vibration from the tympanic membrane for the cochlea
What is the inner ear?
The inner ear converts mechanical vibrations into a nerve impulse
contains cochlea and the semi-circular canals
What is the cochlea?
A fluid filled place, mechanical vibrations cause the liquid to move. The organ of corti (hair cells) move with the fuid and trigger action potential, and mechanoreceptors trigger the impulse in the aufitory nerve where the sensory neurons relay the informstion the the temporal lobe
What is the semi-circular canal?
Fluid filled, for balance. Sensory neurons relay info to the cerbellum (balance)
What us the eustachian tube?
Anotehr ear struvcture, responsible for equalizing pressure.
How does sound travel to the brain?
- Sound waves funneled to tympanic membrane
- Tympanic membrane vibrate
- ossicles vibrate=amplified vibrations
- Ossical vibration cause fluid in cochlea to move
- Moving fluid triggers hair cells (mechanoreceptroes)= action potetnial in auditory nervue
- Info from auditry nerve travels to temproal lobe in the brain
What is the eustachian tube?
Anotehr ear struvcture, responsible for equalizing pressure.
What is the endocrine system?
- Maintains homeostasis (through control of hormones)
Why is the endocrine system slower than the nervous system?
Because the hormones released by the endocrine system must travel through the blood
What are the 3 main parts of the endocrine system?
- Glands
- Hormones
- Receptors on target cells
What do the glands do?
-secretes hormones into bloodstream
What do the hormones do?
- They are chemical messengers (protein or lipid based)
- bind to specific receptors on target cells (and have a specific response)
- have two categories (Trophic/non trophic)
What do trophic hormones do?
Target other glands+ impact hormone secretion ex: TSH
What do non-trophic hormones?
Don’t impact other glands ex: insulin
What does the receptors on target cells do?
- A specific shape for its hormone
- binding hormone causes change at a cellular level
What are the two ways to control hormone levels?
- Negative feedback loop- accumulation of hormone ‘turns off’ a step earlier in pathway
- Positive feedback loop- hormone ‘turns on’/amplifies pathway to accumulate more hormones
KNOW HORMONES
REFER TO SHEET/ PHYSICAL FLASH CARDS
What hormone is released in the hypothalamus?
Hormone: GnRH Target: ptuitary gland effect: impacts release of ptuitary hormones hypersecretion: Increase ptuitary output Hyposecretion: Decrease ptuitary output
What is the pituitary gland?
Master gland, secretes most hormones+most trophiv hormones
Contains 8 hormones (GOATFLAP)
What is the G in GOATFLAP?
Pituitary hormone Growth hormone Target: bones+growth plates Effect: growth Hypersecretion: Gigantism Hyposecretion: dwarfism
What is the O in GOATFLAP?
Pituitary hormone Oxytocin Target: Uterus+mammary glands Effect: Stimulate uterus contraction, and milk release Hypersecretion: pre-term labour Hyposecretion: Delayed labour
What is the A in GOATFLAP?
Pituitary hormone
ADT- antidiuretic hormone
target: Hormones in kidney
Effect: Increase re absorption of H2O intp bloodstrem
hypersecretion: Small amount of concentrated urine (bloating, toxic solutes, ect)
Hyposecretion: Deaibetes insipidus, large amounts of dilute urine=extreme thirst
What is the T in GOATFLAP?
TSH- thyroid stimulating hormone Target: Thyroid effect: Stimulates thyroid to releae thyroxine Hypersecretion: too much thyrozine Hyposecretion: too little thyroxine
What is the F in GOATFLAP?
Pituitary Hormone
FSH- follicle stimulation hormone
Target: ovaries+testies
effect: Stimulates productions of gometes (egg+sperm)
What is the L in GOATFLAP?
Pituitary hormone
LH- lutenizing hormone
Target- ovaries+testies
Effect:Females (ovulation)+ males (testosterone)
What is the 2nd A in GOATFLAP?
Pituitary hormone
ATCH-
Target: adrenal glands
effect: stimulates release of stress hormones
Hypersecretion: kncreassed stress hormones
Hyposecretion: Decreased stress hromones
What is the P in GOATFLAP?
Pituitary hormone
Prolactin
target: Mammary glands
effect: production of milk
What are the thyroid hormones?
Thyroxine and calcitonin
What is thyroxine?
Hormone in thyroid,
Target: Body cells
Effect: Increases metabolic rate (increased cellular respiration. and breakdown glucose)
Hypersecretion: Increased heart ache, anxiety, hot, weight lodd
Hyposecretion: depression, cold, weight gain
How does the body regulate thyroxine levels?
It uses the negative feed back loop,
- the hypothalemus tells the ptuitary gland to release TSJ (Thyroid stimulating hormone)
- Tsh released to thyroid
- Thyroid produces thryoxine
- Accumulation of thyroxin stops pathway at hypothalemus
What is calcitonin?
A hormone in thyroid
Target: Bones
Effect: moves calcium from bloodstream into bones
Hypersecretion: Low blood calcium levels
Hyposecretion: weak bones, high blood calcium levels
What hormones are in the parathyroid?
PTH- parathyroid hormone
What is PTH?
Target: bones and blood cells
Effect: Moves calcium from bones into blood
Hypersecretion: high blood calcium levels
Hyposecretion: Low blood calcium levels
What is the connection between calcitonin and the parathyroid hormone?
They are antagonistic hormones, which means they do everyhting in the opposite way
How does the body regulate blood calcium levels?
With the antagonistic loop
How does the thyroid regulate blood levels in the antagonistic loop?
blood calcium rises, the thyroid releases calcitonin, and the blood calcium decreases (goes into bones) and reclaims equilibrium
How does the parathyroid regulate calcium blood levels in the antagonistic loop?
Blood calcium levels decrease, parathyrpid releases the parathyroid hormone, calcium blood levels increase (out of bones)
How does the parathyroid regulate blood levels in the antagonistic loop?
Blood calcium levels decrease, parathyroid releases the parathyroid hormone, calcium blood levels increase (out of bones)
Which hormones are in the pancreas?
Insulin and glucagon
What are the specialized cells in the pancreas called?
islets of langerhorns
Alpha cells- release glucagon
beta cells- release insulin
What is insulin?
Target: Body cells+liver
Effect: lower blood glucose levels by 1. body cells take in glucose 2. liver converts glucose into glycogen (storage)
Hyposecretion: type 1 diabeties melitus, hyperglycemia (high blood sugar)
hypersecretion: Hypoglycemia (low blood sugar)
What are the 2 types of diabetes?
Diabetes mellitus:
type 1. hyposecretion of insulin: beta cells not making enough insulin, requires insulin shots
type 2. Insulin resistance- result of consistently high blood sugar, receptors become less sensitive to insulin
What is glucagon?
Target: liver cells
Effect: increases blood glucose levels (liver converts glycogen back into glucose)
Hyposecretion: Low blood sugar
Hypersecretion: High blood sugar
How are blood glucose levels regulated with insulin?
- Blood glucose levels get high
- beta cells in pancreas release insulin
- glucose goes into body cells or liver turns into glyvogen
- blood glucose levels decrease
What is the connection between glucagon and insulin?
They are antagonistic
How are blood glucose levels regulated with glucagon?
- Blood glucose levels decrease
- Alpha cells in pancreas release glucagon
- Liver converts glycogen int glucose
- Blood glucose levels rise
How does the body regulate water balance?
With ADH and Aldosterone
How does ADH regulate water in the body?
Made in teh ptuitary,
increases osmotic pressre because of water loss, ex: sweating
Osmoreceptors in hypothalamus detect change (shrink)
Effect+target: nerphrons in kidney, increases reabsorption of h20
How does aldosterone regulate water in the body?
made in adrenal cortex,
decreases blood urine (stress response)
Sensory receptors in kidney detect change
Goes to nephrons in kidney, increases reabsorption of Na+, (h2o follows)
