Homeostasis Topic 1 Flashcards
Where is the Thyroid located/function/hormone name released
neckish part - thyroxine - regulates growth and metabolism
Where is the Hypothalamus located and what is it’s main function
It controls many parts of the body and helps in keeping the body in a stable state called homeostasis
Controls the pituitary gland and links nervous with endocrine system
Where is the Pituitary Gland and what does it do
Major endorcrine gland
Pea sized attached to the base of the brain
Important in controlling growth and development and functioning other endocrine glands.
Releases ADH hormone which regulates water balance
Releases FSH and LH which help with sperm production or menstrual cycle in females
Where is Adrenal Glands and function? (hormone released)
On top of both kidneys
Create adrenaline hormone - which increases levels of activity
Define Homeostasis
Ability to maintain a constant internal enviroment through a mechanism called the ‘negative feedback loop’
Define the negative feedack loop
A type of self regulating system that uses counter responces to correct deviations from a set condition in the internal body enviroment, ultimately to achive homeostasis.
What are the three examples of homeostasis
Temperature regulation
Blood glucose regulation
Water balance
What is the average/normal body temp
37 C
What is a deviation in temperature regulation
When there is excess heat or not enough
What is a correction in temp regulation
Heating up the body if cold and cooling if hot
What is the nergative feedback loop if body temp is too high (Cause - temp - effect)
Exposure to a hot enviroment/exersice - above 37 C - sweating, vasodilation, lowering BMR
What is the nergative feedback loop if body temp is too low (Cause - temp - effect)
Exposure to a cold enviroment - below 37 degree C - Shivering, vasocontriction, increase in BMR
What is the hypothalamus refering to temperature
Temperature sensor and monitors blood as flows through
What is BMR
Basic Metabolic Rate; general metabolism (eating light food vs hard)
What is sweating and what is its purpose
The release of moisture from the sweat glands which evaporate on the skin and cool the skin to reach a lower temperature
What is vasodilation and its purpose
It is the widening of blood vesells close to the skin to release more heat from the blood and lower body temp down to 37 C
What is the effect of decreasing BMR
Less heat is produced
What is shivering and what is its effect
Causes rapid involuntary muscle contraction (shivering) to generate heat to increases body temp
What is vasoconstriction and its effect
The narrowing of blood vessels near the skin in order to conserve heat and keep more closer to the core region like organs in order to increase temp
What is effect of increasing BMR
Increase temp
When does hypothermia occur
When body temp falls below 35C
What are effects of hypothermia
sleepy since brain temp decreases, argumentive, confused, blue tint
Later - dont feel the cold, violent shivering
30C causes death since heart stops
When does hyperthermia occur
When body temp rises above 38C - also refered to heat exhaustion
Heat stroke is when body temp rises above 40C
high temp exposure, high humidity with temp, sweating stops working
What are the effects of hyperthermia/heat stroke
Headaches, dizziness, dry red skin, nausea, profusely sweating
Define glucose
The main energry source (sugar) for cells to function
What is the normal blood glucose level per 100ml
90mg per 100ml
Blood glucose level negative feedback loop (cause - level for cause - effect by loop)
high blood glucose
If you eat and gain lots of sugar - rises above 90mg per 100ml - Insulin is released
Blood glucose level negative feedback loop (cause - level for cause - effect by loop)
low blood glucose
If you exersice or fast etc - less than 90mng per 100ml - Glycagon is stimulated by glucagon and released (stored glucose that insulin forms)
How is glucose level monitored
Hypothalamus detectes and sensores changes which then can be controlled and chnaged by the pancreas
What occurs when blood glucose levels reach over 90mg per 100ml
Insulin released into blood stream from pancreas
Insulin has 2 effects
- increases uptake of glucose from blood
- stimulates conversion of glucose in liver into glycagon
What effects does insulin have
Insulin has 2 effects
- increases uptake of glucose from blood
- stimulates conversion of glucose in liver into gltcagon
What is glycogen
stored glucose
What occurs when blood glucose levels go under 90mg per 100ml
- Stimulates conversion of glycagon into glucose through glucagon
- Releases glucose into blood stream
When do things go wrong (blood glucose level) when below 90mg per 100ml – if negative feedback loop fails - name the thing
HYPOGLYCEMIA
If they fall below 70mg - become fainting, dizzy, nausea, light headed
- easily corrected by small and frequent snacks containing carbohydrates
When do things go wrong (blood glucose level) when above 90mg per 100ml – if negative feedback loop fails - name the thing
HYPERGLYCAEMIA
- high blood sugar level (126mg or above)
- is Type 1 and 2 diabetes (further discussed)
What is TYPE 1 diabetes/hyperglycaemia
Results from inability to produce insulion - have to inject it daily
What is TYPE 2 diabetes/HYPOGLYCEMIA
Body can produce insulin but it has a weakened affect on cells - which is a result of prolonged intake of sugar
Diabetes and lifestyle relationship
80-90% diabetes linked to lifestyle (lack exersice/lots of mass in body)
Exersice can assist bringing levels down
What are they key-functions of a kidney
- Maintain water/salt balance
- Excrete urea (waste product from breaking down excess amino acids)
Where is the nephron located
Medulla (loop of henle) and outer part (cortex for the top parts) - in kidney
Where is the cortex, medulla, renal pelvis, renal artery and vein and ureter located
cortex - outer kidney ish
medulla - triangles in kdiney
renal pelvis -kidney connecting to medullas
ureter - passage to exretory system
renal vien - bottom of renal artery (left of kidney)
renal artery - above renal vein
All steps in a nephron
Blood vessel - bowmans capsule/glomerulus - proximal tubule - loop of henle - distal tubule - collecting duct
Where does ultrafiltration and reabsorption occur
Ultrafiltration - bowman’s capsule
Reabsorption - proximal tubule
Approximately how many nephrons in the kidney
1 million
What occurs in Bowman’s capsule
The glomerulus filters out all substances (except red blood cells)
What happans at proximal tubule
100% glucose/amino acids reasbsorbed back into artery
80% water/ 70% salts (depednign on how much is in body) reabsorbed too
What is ultrafiltration
The removal and filtering of substances from blood (since it isnt very selective) - filters glucose, amino acids, lots of water and salt
What is reabsorption
Replacement of substances back into blood that shouldnt be filtered out of body - occurs along enitire nephron gradually (not just proximal tubule)
How much water in urine after nephron
approx 1-2L of H2O in urine
How many L pass through nephron
Avg person filters 180L/24h yet only produces 1-2L of urine
How does homeostasis work in the kindey when water balance goes above
High intake of water - excess water level - less ADH produced (less ADH means more water away and more urine) - more urine produced
How does homeostasis work in the kindey when water balance goes below
Low intake of twater (from sweating/moisture loss through exhalation) - depleted water levels - more ADH produced - less urine produced/less water in urine
What does ADH do
Chemical produced in brain that causes kidneys to release less water thus less urine produced (more/high ADH = less urine produced
What happans if the kidney failes
Patient must go on dialysis
2 types - Peritoneal/Haemodialysis –> both remove toxins/excess salts & water from blood
in hospital 3/4 times wk for 4h
or
home every night to sleep
Long term goal for patients is to get a kidney transplant and thus live longer but the operation has risks
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Flow chart for nervous system
Stimulus (heat/cold/sound/pressure) –>
Receptor (tastebud/retina/skin/temp receptors) –>
Control (brain or spinal cord) –>
Effectors (Muscles or Glands) –>
Responce (Muscls contract or glands secrete)
What does the CNS (Central nervous system) consist of
Brain and spinal cord
What does PNS (Peripheral nervous system) consist of
Nerves: motor and sensory
Sesory receptors
Effectors: muscles and glands
Sensory neuron simplified diagram
up arrow line----- nucleus (circle above line with a line connecting) line ---- a less than symbol (<)
^—–O—–<
Motor neuron simplified diagram
O————–< (longer than a connector)
nucleus with axon and terminals
Connector neuron simplified diagram
O—–< (shorter than a motor)
nucleus with axon and terminals
What components (labeled names) can you put on sensory neuron
Schwann cell/nucleus (dot in myelin sheath - nucleus ) Myelin sheath (the square things around axon) Axon (the line in the middle) Axon terminals (terminals at the end of the neuron that branch out) Neuron nucleus (nucleus outer circle sprouting out of axon) Cell Body (neuron nucleus cell body that is spruting from axon)
What components (labeled names) can you put on motor neuron
Schwann cell/nucleus (dot in myelin sheath - nucleus ) Myelin sheath (the square things around axon) Axon (the line in the middle) Axon terminals (terminals at the end of the neuron that branch out)
Cell Body (neuron nucleus cell body that is AT THE START IF THE NEURON) Neuron nucleus (nucleus inside cell body at start of motor neuuron) Cell body dandrites (dandrites sprouting form cell body at start of neuron)
What is the function of the MYELIN SHEATH
- Allows electircal impulses to transmit quickly/efficiently
- insulates neuron against other neuron impulses (prevents ‘cross circuits’)
Simplified neural pathway steps
Receptor/stimilus (like skin/pressure) - nerve impulse sent through sensory neuron - terminal + synapse to connector neuron/motor neuron - synapse connecting to effector like muscle or gland
What does sensory/motor link to
Sensory neurons link receptors to CNS
Motor neurons link CNS to effectors
Steps of the synapse
Nerve impulse arrives at end of neuron
Arrial of impulse results in release of chemical transmitter substance from the end of the neuron (neurotransmitters)
When sufficient number of neurotransimtters accumulae on motor neuron (or receptors) a new nevre impulse is generated (or if effector - secretse hormone or contracts muscle)
3 Roles of a synapse
- To allow for only a one way direction
- For forming/maintaining memory/memory loss –> new or different neural pathways can form in brain (which are considered memories)
- Act as a filter which determines if a message should be passed on or not
All labaled things on a synapse
axon terminals (start of synapse)
Synaptic vesicles (besicles that hold neurotransmitters ready to be released)
Synaptic space (space between in the synapse) - 40 nanometers wide
Postsynaptic neuron (neuron after synapse)
Chemical transmitter substance/neurotransmitter (stuff that is realesed to postsynaptic neuron to pass on neural impulse
Receptor site (Locationw eher the neurotransmitters go to)
What is a REFLEX RESPONCE
Automatic involuntary/rapid responce to stimilus (spinal cord is used instead of brain since without thinking - reaction is quicker)
Roles of the reflex responce
- Prevent harm to body like hot objects
- To create rapid adjustments to stimuli (like if tongue touches food, more saliva is produced)
- Allow continues functions like heart beat/breathing/digestion
Examples of reflex responce are
breathing blinking coughing constriction/dilation of pupils according to light yawning sneezing kneww jerk jerking hand from hot substance
What is the reflex arc pathway
Hand/stimili/responce (pain receptors) - send nerve impulse to sensory neuron - spinal cord (connector neuron) - motor neuron - muscle/gland to contract/secrete
What are the 2 systems that can respond to stimili
Endocrine system
Nervous system
Steps in endocrine system general
- Gland stimulated by motor neuron
- Gland released into bloodstream
- Hormone is circulated through bloodstream
- Hormone reaches target organ through bloodstream and produces the viable responce
Where is pancreas located and role/hormone
Releases insulin which reduces blood glucose levels
What do testes do and release
Testosterone - sperm production
Ovaries do/realese?
Oestrogen & Progesterone hormones which effect and cause mestrual cycle in females
What hormones are called steroids
Testosterone, Oestrogen, Progesterone
Compare the nervous and hormonal systems in their responding to stimuli
Nervous –> fast transmission, electrical & chemical type, pathways are neurons, short lived duration
Hormonal –> slower transmission, chemical type, travels through the pathway ‘bloodstream’, long lived affect (prolonged)
What are base pairs
Things in between DNA sugar-phosphate backbone
What are the sides of dna called
Sugar-Phosphate backbone (one side starts with a extra phosphate and other ends in an extra)
What is nucleotide
Sugar, phosphate and nucleic acid together (1 of each)
How are sugar and phosphate bonded
covalent
How are the nuclei acids (base pairs) bonded
Hydrogen bonds since made of hydrogen
What is opposite to A in DNA
T
Opposite to G in DNA
C
Opposite to T in DNA
A
Opposite to C in DNA
G
What is the function of DNA
Dna is blueprint/code for making proteins –> proteins determine inheritable traits and characteristics
DNA –> protien syntheis to create PROTEIN –> TRAITS AND CHARCATERSITICS
PROTEIN SYNTHESIS is the name of the process
What is the name of A nucleic acid
Adenine
What is the name of T nucleic acid
Thymine
What is the name of G nucleic acid
Guanine
What is the name of C nucleic acid
Cystine
name of U nucleic acid
Uracel
What does T turn into when into RNA
A
What does A turn into when into RNA
U
How does transcription occur
- DNA unzips hydrogen bonds (which are weak)
- mRNA nucleic acids (A, U, G, C) pair with DNA code to the gene needed
- mRNA moves out of nucleus through a pore - to the ribosome located in cytoplasm in cell
How does translation occur
- Ribosome binds to the start of code on mRNA (AUG)
- Ribosome reads code in mRNA by pairing mRNA triplet codon with complementary tRNA codon - bringing amino acid to polypeptide
- Polypeptide chain is folded into a protein
How is down syndrome occur
Result of additional chromosone 21
What is a ‘A’ point mutation/ (gene mutations) and 2 examples of point mutation
Is a result of a change in the base sequence (e.g. ATGC), within the gene region of DNA
Typically occurs when DNA is copied prior cell division or during transcription
Substitution, Addition and Deletion mutation
What is substitution mutation
Mutation which results when one/more bases is replaced by a different base (T –> G) –> forming a different amino acid
What is deletion mutation
When 1/more bases is removed from DNA sequence - resulting in ‘frame shift’ mutation
Often results in an unuseful protein being formed
B Mutations - Chromosonne mutations explain
Occur when ‘cell division’ (meiosis) results in
- Alteration to chromosome structure
- Unequal separation of chromosomes during cell division
Example: Down syndrome (Trisomy 21) since an extra copy of 12’st chromosome
ALTERATION IN THE NUMBER OF CHROMOSOMES 45 or 47 instead of normal 46
What is the name of a square for allele stuff
Punnett square
Define GENE
A sequence that determines an inheritable trait (typically by coding for protein)
Define Allele
Particular variation of a gene (gene for coat colour in guinea pigs)
Define a DOMINANT ALLELE/TRAIT
An ALLELE/TRAIT expressed over it’s recessive form (B)
Define a RECESSIVE ALLELE/TRAIT
An ALLELE/TRAIT that is only expressed in an absence of dominant allele (b)
Define a PHENOTYPE
The trait/characteristic that is expressed (often visible) e.g. a black coat, white coat colours
Define a GENOTYPE
Combination of alleles (BB, bb, Bb)
Define a HOMOZYGOUS
having the same alleles (BB/bb)
Define a HETEROZYGOUS
having differenet alleles (Bb)
Describe a Bb
Heterozygous
Describe a BB
Dominant Homozygous
Describe a bb
Recessive Homozygous
What is a Addition mutation
Point mutation - adds a base to DNA resulting in ‘frame shift’
What is a frame shift
Addition or Deletion causes a shift in amino acids result
What is AUTOSOMAL DOMINANCE
Dominance occurs when an ALLELE is completely masks the presence of the other
Human Autosomal Chromosomes are the first 22 pairs
Define carrier
Term used for heterozygous individuals who has a recessive allele that results in a disease/disorder carrier
Carries have normal health
What is Haeomophilia
Condition where blood doesn’t clot normally
What is CODOMINANCE
Both parental phenotypes are individually expressed in a phenotype of heterozygous individual (some white and some pink petals)
What is INCOMPLETE DOMINANCE
When a phenotype of heterozygous individual is intermediate (has a blending effect) between the phenotypes of homozygous parents (Red petals and white causes a PINK petals)
Define evolution
Change in genetic composition (different alleles) of a population over time (which may lead to a new or different species being formed)
Change in genetic composition
What is natural selection
- Major dividing force of evolution
- The concept that nature ‘selects’ those organisms best adapted to survive in a particular environment (or AGAINST those that are not)
Adaptations result genetic variation
If a organism has a genetic variation that leads to a useful adaptation (in a particular environment) - then the organism is more likely to survive/reproduce and pass on an adaptation to some of its offspring (survival of the fittest)
What evidence is there of evolution
Fossil evidence - mold fossil, true form fossil, cast fossil, trace fossil, unaltered/preserved fossil
DNA evidence - human/chimp DNA is 98% identical to humans
Define a fossil
Remains/traces of any organism that lived in geological past
What is DNA
Dna is blueprint/code for making proteins –> proteins determine inheritable traits and characteristics
DNA –> protien syntheis to create PROTEIN –> TRAITS AND CHARCATERSITICS
Differnece between chromosone and gene
Chromosone is a part of DNA and Gene part of chromosone
How many chromosomes in a cell
46 Chromosones
Difference between translation and transcription
Translation - converting mRNA to proteins at ribosome
Transcirption - copying genes in nucleas
How does translation/transcriptiion happen
DNA cannot leave nucleas
Protein is made outside nucleas on Ribosome
Code is transferred by mRNA (messenger)
- A copy of DNA is made into the form of mRNA
- mRNA exits nucleas and entters cytoplasm (where proteins are produced)
- Ribosome attaches to mRNA which creates amino acids linked together to form a particular protein
