Human Bio Exam #3

what is the role of the circulatory system?

transport O2 to tissues and CO2 away from tissues

what is the role of the respiratory system?

exchange O2 and CO2 between air and blood

how is epithelial tissue involved in the respiratory system?

diffusion across alveoli and capillaries

secretes mucus across respiratory tract

how is connective tissue involved in the respiratory system?

blood exchanges gases with lungs

cartilage makes up part of nose, trachea, bronchi, and larynx

how is nervous tissue involved in the respiratory system?

autonomic nervous system controls smooth muscle in the bronchi

how is muscle tissue involved in the respiratory system?

smooth muscle in lungs regulates airflow to alveoli

skeletal muscle in diaphragm expands lungs

what is the order of organs/structures in the respiratory system?

nose → pharynx → larynx → trachea → bronchi → (lung) → bronchioles → alveoli

what does the nose do?

breathing

immunity

sense of smell

warms air

filters particles

what is the pharynx?

throat

passageway for swallowed food and air

what is the larynx?

voice box

epiglottis covers larynx opening, providing protection by diverting incoming food

vibration of vocal cords produces sound

what is the trachea?

windpipe

tube with cartilage rings for air passage

where are the bronchi?

branch off trachea

one for each lung

lined with cilia which move debris up and out

what are the bronchioles?

branch off bronchi

no cartilage, only epithelium and smooth muscle

lined with cilia which move debris up and out

what are the alveoli?

tiny sacs with walls made of epithelial tissue that is one cell thick

what do the goblet cells scattered throughout cilia of bronchi and bronchioles do?

secrete mucus which helps cilia to trap harmful particles and microbes and move them up and out

how is one’s rate of breathing determined?

by their need to get rid of CO2

what is the diaphragm?

skeletal muscle extending across bottom of the rib cage

what happens when the diaphragm contracts?

it moves downwards which increases the lung’s volume

as the chest cavity’s volume increases, its air pressure decreases

therefore air rushes in

= inhalation

what happens when the diaphragm relaxes?

it moves upward which decreases the lung’s volume

as the chest cavity’s volume decreases, its air pressure decreases

therefore air leaves the lungs

= exhalation

how does the process of gas exchange between the air we breathe in and our blood work?

• the air entering our alveoli contains O2 and CO2

• blood entering the capillaries surrounding alveoli contains lots of O2 and little CO2

• O2 diffuses from alveoli to capillary via simple diffusion

• CO2 diffuses from capillary to alveoli via simple diffusion

• therefore we breathe out the unnecessary CO2 and keep the O2

what affects how well molecules can move in the blood when we breathe air (O2 and CO2) in?

thickness of cells (respiratory membrane)

air pressure

surface area of alveoli

what does the liver do?

processes blood plasma by storing and detoxifying molecules

what does the hepatic artery do?

transports O2 rich blood from the aorta to the liver

what does the hepatic portal vein do?

transports nutrient rich, O2 poor blood from digestive organs to the liver

what do the hepatic lobules that make up the liver do?

basic structural and functional unit of the liver

made of hepatocytes

what do hepatocytes do?

constantly process molecules from blood for storage and detoxification

protein metabolism is body creates toxic ammonia, liver converts to urea

glycogen storage

makes proteins that are necessary for blood clotting

what do kupffer cells do?

recycle/break down hemoglobin from RBCs broken down in the spleen

byproduct = bilirubin which is added to bile

can signal to hepatocytes to exit G0 and enter cell cycle if liver needs to regenerate

what do stellate (ito) cells do?

store vitamins, fat, and co-factors (chemicals needed for enzyme functions)

can signal to hepatocytes to exit G0 and enter cell cycle if liver needs to regenerate

what do renal arteries do?

bring blood to the kidneys

what do renal veins do?

take blood away from kidneys

how does the urinary system regulate the contents of plasma?

1. protein metabolism: creates nitrogenous waste

2. liver converts ammonia in blood to urea

3. urinary system excretes urea in the urine

what are the basic steps to urine formation?

filtration, reabsorption, secretion, and excretion

what is filtration in urine formation?

liquid plasma of blood if transferred from blood vessel to nephron of the kidney

• high BP in glomerulus capillaries pushes any small molecules across porous capillary bed cell layer

• only selective based on size of molecules (blood cells and large proteins = too large)

what is reabsorption in urine formation?

“good” molecules return from nephron to blood vessels (peritubular capillaries)

• Na+, Cl-, glucose, and amino acids are actively transported back to blood in proximal tubule

• water reabsorbed via osmosis in loop of henle

what is secretion in urine formation?

additional substances from blood are actively transported and secreted into the nephron to be eliminated

what is excretion in urine formation?

removal of blood waste from nephron to ureters

additional H2O may be reabsorbed

dependent on ADH hormones

what are kidney stones?

crystals formed from urine made of calcium, phosphorus, uric acid, and protein

may block ureters and cause urine to back up into nephrons which would/could destroy them

what is a UTI?

bacterial infection

urethra microbiome typically protects against invading microbes

invaders can colonize and move up urinary tract

what is hypertension?

creates higher BP in glomeruli capillaries and can damage them if persistent

what is Type II Diabetes?

when blood sugar is high, solute concentration of blood rises too

causes more reabsorption of water and therefore high blood volume and pressure which damages nephrons

what is a nephron?

filtration unit of the kidney

what does bowman’s capsule do?

filtration of small molecules out of blood using blood pressure against capillary walls

what does the proximal tubule do?

reabsorption of glucose and amino acids via active transport

what does the loop of henle do?

reabsorption of water via osmosis

what does the distal tubule do?

secretion of toxins/drugs via active transport

what are the two divisions of the nervous system?

central nervous system (CNS)

• brain and spinal cord

peripheral nervous system (PNS)

• nerves outside CNS

what does the CNS do?

receive, process, and transfer info

what are the two divisions of the PNS and what do they do?

sensory division - carries info toward CNS

motor division - carried info away from CNS

what do neuroglia do?

support neurons

what are neurons?

specialized cells that transmit electrical signals throughout the body to communicate

what do dendrites do?

receive signals

chemical signaling

what do axons do?

transmit signal along neuron’s length

electrical signaling

what do synaptic terminals do?

transfer signal to another neuron or muscle cell

chemical signaling

what is a resting potential?

must be established before an action potential

neuron’s electrical charge when not sending a signal → inside is slightly negative (70mV)

how is resting potential established?

Na+/K+ pumps transport 3 Na+ out, 2 Ka+ in (movement is up concentration gradient)

*ATP is necessary

what is an action potential?

sudden reversal of membrane voltage that moves down axon like a wave

how does an action potential work?

Na+/K+ pumps open, moving down gradient

Na+ rushes in which makes inside temporarily positive = depolarization

stimulus must depolarize membrane above -55mV (threshold level) for Na+ pumps to open

closed Na+ channels make sure action potential does not travel backwards

what is the “all or nothing” principle?

stimulus must be strong enough to overcome the threshold = action potential either happens or it doesn’t

what are myelin sheaths and what do they do?

insulated axons

made by schwann cells wrapping around the axon

saves neuron energy

speeds up transmission of impulses

what is saltatory conduction?

leaping pattern of action potential conduction (faster movement) that is achieved because of the myelin sheath

what is multiple sclerosis (MS)?

progressive damage of myelin sheath in brain/spinal cord

weakness, visual impairment, incontinence

what is amyotrophic later sclerosis (ALS)?

progressive damage to myelin sheath in motor area of spinal cord

progressive weakening and wasting of skeletal muscle

how are signals sent from a neuron to other cells?

the synapse

what does the synapse do?

specialized junction where axon communicates with another cell

neurotransmitters stored in vesicles in axon terminals are released into the synaptic cleft as the action potential causes vesicles to fuse with the membrane and release their contents

what does the response in postsynaptic cells depend on?

how many neurons are forming synapses with it

whether neurons forming synapses are excitatory or inhibitory

what is convergence?

1 neuron receives input from many others

what is divergence?

1 neuron sends AP to multiple others

what is a sensory neuron?

a cell that detects a stimulus and turns it into an action potential

what four things do we sense about our environment?

• energy waves (sound and light)

• molecular shapes (smell and taste)

• temperature

• physical properties (smoothness and sharpness(

what stimulus do mechanoreceptors respond to?

mechanical charge in dendritic region

respond to movement of fluid in cochlea

what stimulus do thermoreceptors respond to?

heat or cold

what stimulus do pain receptors (nociceptors) respond to?

tissue damage or excessive heat

what stimulus do chemoreceptros respond to?

presence of chemicals

what stimulus do photoreceptors respond to?

light

what does wavelength have to so with sight?

each distinct wavelength is perceived by the eyes/brain as a different color

“colors” of light are absorbed by objects, whatever is not absorbed is reflected and stimulates that specific color wavelength detecting cone

what is the pathway of light through the eye?

enters eye through cornea and pupil

focused by lens onto retina

converted into signals that travel through optic nerve

what is the cornea?

clear front covering of eye

bends light toward the pupil

what is the pupil?

opening that allows light into the eye

what is the lens?

changes shape to allow eye to focus light

what is the retina?

light sensitive sheet or neuronal tissue in the lining of the eye

what is the optic nerve?

sensory neuron

sends signals to the brain

what is the fovea?

area of retina responsible for central vision

point at which visual acuity is at its highest

what does it mean for someone to by astigmatic?

trouble with depth perception and visual acuity

what is the difference between nearsighted and farsighted?

near: trouble seeing far away

far: trouble seeing near

what are cone cells?

detect different colors

require brightly lit environments

what are rod cells?

detect dim lights

used for night vision

what are bipolar cells?

transmit signals from rods/cones to ganglion cells

help determine shape of objects

what are ganglion cells?

send information from rod/cone and bipolar cells to brain through the optic nerve

what four cells are in the retina?

cone, rod, bipolar, ganglion

where do signals from the optic nerve go?

relayed to primary visual cortex in the occipital lobe

what is sound?

pressure wave of air

what is frequency?

pitch tone

• high frequency = high tone

• low frequency = low tone

what is amplitude?

loudness

• high amplitude = loud

• low amplitude = quiet

what is the pathway of sound through the ear?

pinna concentrates sound into auditory canal where sound waves vibrate tympanic membrane which are converted into signals

what is the pinna?

outer visible portion of ear

directs sound waves to the auditory canal

what is the auditory canal?

directs sound waves to the tympanic membrane

what is the tympanic membrane?

ear drum

separates outer and middle ear

vibrates in response to sound waves → this movement is transferred to ossicles then to movement of liquid in cochlea

what are the ossicles?

3 small bones

• malleus = hammer

• incus = anvil

• stapes = stirrup

hear different frequencies depending on size of bones

what is the auditory tube?

connects to throat

equalizes pressure

what is the cochlea?

filled with fluid → movement of fluid stimulates cilia of cells lining cochlea

inner ear turns waves in fluid to signals to brain through cilia