B9-B10 (human Reproduction + Nervous System) Flashcards
What is stimulus?
Changed in the environment
What does the nervous system do?
Detects and respond to changes in the environment (stimulus)
Avoid danger
Detect food
Learn from experience
What are receptors?
Receptors pick up stimuli
More receptors-> more sensitive
What are the sense organs?
Tongue, eyes, nose, ears, skin
What are the organs in CNS and what does the CNS do?
Brain and spinal cord
Processes and coordinates sensory data + sends out motor commands
What are the parts of the PNS and what does the PNS do?
Peripheral nerves (nerve-> bundle of neurons)
Takes information from the organs to the CNS + from CNS to effectors
Explain the pathway of electric impulses through the nervous system
Receptor (stimulus) -> sensory neurons -> brain -> motor neurons -> effectors (response)
What are reflexes?
Automatic and rapid response to stimuli
Often protect from danger and doesn’t reach the brain until after the reaction has happened
Describe the path of an electric impulse through the nervous system for a reflex
Stimulus -> receptors -> sensory nerves -> relay neurons (spinal cord) (info is relayed not processed because reflexes need to be quick) -> motor nerves -> effectors
What are the differences and similaires between voluntary and involuntary movement?
Voluntary:
Slow
Conscious thought
Passes via the brain
Majority of movement
Involuntary (reflex):
Quick
Relay neurons in spinal cord
Protect the body
Both:
Both use sensory and motor neurons
Both use receptors and effectors
Involves electrical impulses
Using a diagram name and describe the functions of each part of the eye
Lens
Magnifying glass (20% of the magnifying)
Focus on further and closer things
Focuses light in the retina
Ciliary muscles
Squeezes lens -> thicker and thinner
Pupil
Hole in the center of the eye
Light enters the eye
Cornea
Protects the eye
Magnifying glass (80% of the magnifying)
Usually clear and first place light enters
Iris
Controls the amount of light entering the eye
Ring of muscle around the pupil
Muscles in the iris:
Circular and radial -> antagonistic muscles
Bright light/pupil contract -> circular contract, radial relax
Dim light/pupil dilate -> circular relax, radial contract
Suspensory ligaments
Suspense the lens
Connects to ciliary muscle
Blind spot
All receptors in the retina connect to this point (means no receptors here -> cannot see -> brain fills in image)
Optic nerve
Sensory neurons that carry impulses to brain
Retina -> brain
Sclera
White outer layer
Maintain shape and protect
Retina
Layered brain tissue
Photoreceptors
Rod -> peripheral, motion, dim light
Cone -> middle, color (red, blue, green), details (bright light)
What does accommodation require to happen?
Lens must change shape to focus light differently based on if you are looking at a closer or further object
Create a diagram showing how light enters the eye when looking at an:
A) close object
B) distant object
Close:
Thicker lens
Light enter is wider
Relaxed suspensory ligament
Contracted muscle
More refraction
Distant:
Thinner lens
Light enter is thinner
Tight suspensory ligament
Relaxed muscles
Less refraction
Draw a diagram and explain what causes:
A) short sightedness
B) long sightedness
And how it can be corrected
Fixed by glasses by focusing the focal point so it lands on the retina
Short sightedness:
Light focuses too early (before retina)
Causes:
Long eyeballs
Thick lens
Fix:
Concave/diverging lense
Spreads light rays
Long sightedness:
Light focuses to late (after retina)
Causes:
Short eyeball
Thin lens
Fix:
Convex/converging lense
Brings light to a focus
What are hormones?
Produced by glands
Chemical messengers released into the bloodstream
Alters activity of target organs (later destroyed but liver)
What does adrenaline do and how is it made?
Responds to danger -> fight or flight
Adrenal gland (on top of the kidneys) -> affects multiple organs
Describe the hormone response pathway
Adrenal gland releases adrenaline -> adrenaline is transported in the bloodstream -> receptors detect adrenaline -> effectors respond to adrenaline
What are some examples of effectors ?
Heart, stomach, eye (iris), muscles, blood vessels, brain
What are the effects of Adrenaline and why do they happen?
Increased blood glucose
More respiration -> more energy
Increased blood pressure
Blood travels faster -> more oxygen, glucose, adrenaline, take away waste
Expanding air passages of lungs
Allows more oxygen to enter and more CO2 to leave -> more respiration
Enlarged pupil
More light enters through the pupil -> see better
Redistributes blood to muscle and vital organs
Helps them work efficiently
Compare hormone and nerve responses
Hormone response:
Chemical signal
Relatively slow
Released by glands
Travels in the bloodstream
Effector -> generally organs
Nerve response:
Electrical signal
Relatively fast
Triggered by receptors
Travel along neurons
Effectors -> generally muscles
What is negative feedback?
Change occurs in the opposite direction to bring conditions back to normal
What is homeostasis?
Mechanism to maintain a constant and stable and internal environment (37°C)
How is temperature controlled in the body?
Monitored and controlled by temperature receptors in the skin and brain
Receptors -> detect changing temps in the blood (body cold -> blood cold -> brain cold)
What is the thermoregulatory center of the brain?
Hypothalamus
Impulses from brain trigger reaction
Explain what happens to the body when it is:
A) too warm
B) too cold
And why
Too warm (heat stroke):
Vasodilation
-> blood vessels increase in size
-> more heat radiates from the body
Sweating
-> heat energy is transferred to the sweat and evaporates
Hairs flatten
All to increase heat loss
Too cold (hypothermia):
Vasoconstriction
-> blood vessels decrease in size
-> reduces amount of heat lost
Shivering
-> more respiration
Less sweat
Hair stand up
-> insulating layer
All so reduce heat loss
Look at a diagram and label + explain the functions of all the parts of the skin
Melanocyte:
Cell in the epidermis that produces melanin (protection from the sun)
Sweat/suboriferous glands:
Tube shaped glands
produce sweat on the skin
Epidermis
Sebaceous glands:
Sack shaped gland
Releases oily liquid to lubricate and soften skin
Dermis next to hair follicle
Hair shaft:
Part of hair above skin
Hair erector muscle:
Muscles that connects hair follicle to skin
Contract -> goosebumps
Hair follicle:
Tube shaped sheath
Surrounds hair under the skin
Nourishes hair and growing point
Dermis+epidermis
Blood vessel:
Carries blood
Epidermis:
Outer layer of skin
Dermis/cutis:
Layer under epidermis
Subcutaneous tissue:
Fatty tissue
Under dermis
Why is too much/little glucose bad for the cells in the body?
Too much:
Excess glucose makes blood plasma+tissue fluid around the cells too concentrated
Damages the cells-> too much water diffuses out -> osmosis
Too little:
Low glucose makes cells swell but and burst
A result of too much water diffusing in to have the same water concentration as its surrounding -> lysis
How is glucose regulated?
Glucose levels and concentrations are regulated by the pancreas using 2 different hormones
INSULIN:
Released by pancreas when blood sugar is high
Stimulates liver to convert glucose -> glycogen (groups of glucose, stored in liver and muscles)
GLUCAGON:
Released when blood sugar is low
Stimulates liver to convert glycogen -> glucose
Blood glucose high -> cells in pancreas detect change -> pancreas secretes insulin -> glucose stored as glycogen -> blood glucose decreases -> blood glucose too low -> cells in pancreas detect change -> pancreas secretes glucagon -> glycogen converted to glucose -> blood glucose increases -> back to start
Hyper/hypoglycemia: what is it, causes, and treatment
Hypoglycemia:
Blood sugar drops below normal range
result of: extreme exercise, missed meals, too much insulin
Treatment: glucose IV drip or food
Hyperglycemia:
Blood sugar because higher than a normal range
Result of: too many carbs, lack of exercise, too little insulin
Treatment: injection insulin
What is diabetes?
A disorder that causes blood sugar levels to be above a normal range and go into dangerous levels
-> a result of pancreas not producing enough insulin
How do type 1 and type 2 diabetes lead to high blood sugar? What are the symptoms of both types ?
Type 1:
Immune system attacks and destroys insulin producing cells in pancreas
An immune disorder
Type 2:
Pancreas doesn’t produce enough insulin or the body has developed an insulin resistance
Symptoms:
1-> extreme weight loss
2-> infections, numbness at hands and feet, gum problems
1+2-> thirst, hunger, fatigue, increased urination
Compare asexual and sexual reproduction
Asexual:
Produces genetically identical organisms
Mitosis (exact copies)
One parent
Quick (no variation and susceptible to disease)
Sexual:
Produces genetically different organisms
Meiosis (makes genetically different organisms) (gamete and zygote)
Mitosis (growth after fertilisation)
Gender: female -> XX and male -> XY
Slow (but there is variation)
What are the advantages and disadvantages of asexual and sexual reproduction
Asexual:
Advantages:
Identical organisms (quick and adapted to the environment)
Only one parent
Disadvantages:
Environment can change
If a specific species they interact with goes extinct->could also go extinct
Susceptible to disease
Sexual:
Advantages:
Variation of offspring
Disadvantages:
2 parents -> takes time
Explain haploids and diploids (and examples)
Haploid:
One copy of each chromosome
Ex: gametes (egg and sperms)
Diploid:
2 set of each chromosome
Ex: 2 gametes fuse to form a zygote
Label a diagram of the female reproductive system and explain the function of each part
Oviduct/fallopian tube:
Carries ovum from ovary to uterus
Where the egg becomes fertilized
Ovary:
Produces ova (egg/gametes)
After puberty -> ovum released around every 28 days
Cervix:
Ring of muscle at opening of uterus and top of vagina
Uterus/womb:
If egg fertilises it is implanted onto the walls of the uterus and becomes a fetus
Vagina:
Receives the penis during sex
Sperm is deposited
Label a diagram of the male reproductive system and explain the function of each part
Seminal vesicle:
Creates ingredients for semen
Ureter:
Connects kidneys to urinary bladder
Bladder:
Hold urine until it can be excreted
Prostate gland:
Secretes fluid for sperm to swim in -> forms semen
Penis:
Transfers semen to vagina during sex
Urethra:
Carries urine and semen out of the body
Scrotum:
A sac of skin which holds the testes
Testes/testis:
Produces sperm
Epididymus:
Stores sperm
Sperm duct:
Carries sperm to outside the body
What is puberty?
When boys and girls become sexually mature
Controlled by hormones
Sex cells produced and released
Several years to complete
What is the menstrual cycle?
Female body prepares for the pregnancy
Makes sure uterus is in perfect conditions for implantation (28 days long)
Explain what happens during the menstrual cycle (including days)
Day 1-5:
Menstruation
Interns lining is shed
Day 6-13:
Uterus lining is built up
Egg matures in the uterus
Day 14:
Uterus lining at its thickest (prime)
Egg released from ovary (ovulation)
Day 15-28:
If fertilisation:
Egg implants onto lining
Uterus lining is maintained
No fertilisation:
No implantation and egg dies
Uterus lining starts to break down
What are the hormones related to the menstrual cycle (the 2 we learned about)
Oestrogen and progesterone
Explain the functions of oestrogen and progesterone
Oestrogen:
Rises from day one and peaks on day 14 (just before egg is released)
Uterus lining start thickening
Egg begins to mature
Progesterone:
Low day 1-14
Rises once ovulation had occurred
Increasing levels-> lining thickens (maintains lining while implantation can occur)
Decreasing levels-> lining shed (menstruation)
Both will increase if fertilisation occurs
Describe the journey of the sperm
Released into vagina
Cervix
Uterus
Swims up oviduct (why it has tail)
Takes around 10h
Millions are made -> strongest survive
Quickly made -> many are deformed
Describe how fertilisation occurs
Sperm reaches egg -> pushes through cell membrane (tail lost)
Enzymes in sperm break through the cell membrane
Goes in -> wall forms -> other sperm cannot enter
Travels to uterus -> implantation (around 3 day process)
Nucleus of sperm and egg fuse -> zygote
-> 23 pairs of chromosomes (2 sets)
Zygotes divides into 2 cells with identical sets of chromosomes and continue to form embryo
-> mitosis
What is the placenta?
Provides nutrients, oxygen, removes waste
Connected to umbilical cord
Secretes hormones -> maintain pregnancy
Developed by embryo
What is the function of an amniotic sac?
Encloses the embryo and secretes amniotic fluid
Protect the embryo from sudden movements
What is HIV?
Human immunodeficiency virus
Affects CD4 (T-lymphocytes) in immune system
-> virus replicates and destroys the cells
What are CD4 cells?
Lymphocytes (white blood cells) that protect against pathogens
What does it mean to be HIV positive?
Body creates antibodies to combat the virus
If detected in body -> HIV positive
How is HIV transmitted?
Can be transmitted from anyone with HIV and depends on viral load (HIV particles/ml)
Blood (sharing needles, blood transfusion (highly unlikely)
Vaginal fluid/semen (sexual intercourse)
Breast milk (baby drinking)
Birth (mother gives birth while infected)
How can HIV be prevented?
Condoms
Not sharing drug injection equipment
Protect cut, sores, eyes mouth from blood
Antiretroviral drug during pregnancy
No breastfeeding
What are common myths of HIV?
Bug bites (no bodily fluids injected)
Kissing/spitting/mouth to mouth contact (saliva and tears contains enzymes that destroy)
Contact with healthy skin
Sharing cutlery, bath, towel, swimming pool
What is AIDS?
Acquired immunodeficiency syndrome (syndrome: group of health disorders that make up a disease)
HIV becomes AIDS
At what point do you have AIDS?
HIV becomes AIDS when there is less that 200 CD4 cells/ml or less than 14% of CD4 cells
What are the effects of AIDS?
Leaves patient susceptible to secondary infections
Ex: PCP -> pneumonia
KS -> Kaposis sarcoma -> cancer
CMV -> cytomegalovirus -> virus that infects eye
Candida -> fungal infection
Effects CD4 cells -> slowly wears down immune system and makes it harder to combat pathogens
What are the 7 stages of HIV infection?
Binding:
HIV virus binds to surface of CD4 cells
Fusion:
Virus fuses with CD4 membrane and injects genetic material (RNA)
Reverse transcription:
Enzymes from virus RNA -> DNA
Integration:
Virus DNA inserts into CD4 cells DNA
Replication:
Produces virus particles along with its own proteins
Assembly:
Virus particles combine to create HIV virus
Budding:
HIV virus burst from membrane into blood stream
Infects other CD4 cells
Host cell is destroyed
Label a diagram with the 7 stages of HIV infection
Good luck girlie pop
How is HIV/AIDS treated?
Aim of treatment:
Reduce the viral load to undetectable levels
-> too low to detect or damage the immune system
Antiretroviral drugs (ARV)
-> stops virus from replicating and allows immune system to repair itself
-> combination of drugs
-> miss one dose -> failure of treatment
-> side effects: nausea, diarrhea, skin/body reactions, sleep difficulties
