Biology -Homeostasis

What are Antagonistic Hormones?

• Hormones that have the opposite effect on the same body process to maintain balance (homeostasis)

• They work together through negative feedback

• One works to increase the effect, while the other decreaes it.

What is an example of a Atagonistic Hormone?

• Insulin and Glucagon

• Insulin lowers blood glucose

• Glucagon raises blood glucoe

Which hormone triggers ovulation?

• LH

Explain Synaptic Transmission

• the process by which a nerve signal passes from one neuron to another.

• when an electrical impulse reaches the axon terminal, it triggers the release of neurotransmitters

• these chemicals cross the synaptic cleft (tiny gaps between neurons)

• these neuromtransmitters bind to receptors on the next neuron’s membrane.

• the binding opens ion channels and can start a new electrical impulse in the next neuron if the signal is strong enough.

What is a reflex arc?

• the pathway followed by a nerve impulse during a reflex action, which is a fast, automatic response to the stimulus.

Explain the process of the reflex arc

• a stimulis is detected by receptors in the skin

• the impulse travels along a sensory neuron to the spinal cord.

• an interneuron in the spinal cord processes the signal and passes it on.

• The impulse than travels along a neuron to the effector

• the effector then acts immediately

What is action potential?

• the electrical signal that travels along the neuron and has a negative charge as rest

Explain the process of action potential

• When a stimulus is strong enough, Na+ channels open and Na+rushes the neuron.

• causes depolarization making the neuron +

• Then K+ channels open and K+ flows out restoring the negative charge in a process called repolarization.

• the neuron then enters a refractory period.

What is the counter current mechanism?

• How kidneys preserve water and produce concentrated urine

Explain the steps of the counter current mechanism

• fluid flows in the opposite direction in to the limbs of the loop of henle.

• in the descending limb, the tubule is permable to water, so water leaves by osomosis and the filtrate becomes more concentrated.

• in the ascending limb, the tubule is impermable to water, so Na+ and Cl- are transported out, making the filtrate less concentrated.

• this oposite flow creates a concentration gradient in the medulla.

What are the kidney hormones + functions?

• Antiduretic hormone (ADH): increases water absorption in the kidneys

• aldosterone: increase Na+ reabsorption and K+ secretion

What are the calcium balance hormones?

• Parathyroid: increase calcium levels

• Calcatonin: decreases calcium levels

What are the male reproductive hormones?

• GnRH: stimulates LH & FSH release

• LH: stimulates testosterone production

• FSH: stimulates spermatogenesis

• Testosterone: sperm production

What are the female reproductive hormones?

• GnRH: Stimulates LH and FSH release

• FSH: stimulates follicle development + estrogen

• LH: causes ovulation

• Estrogen: thickens uterine lining

• proestrogen:” maintains uterine lining

What is a steroid hormone?

• Made of cholesterol, fat soluble, passes through cell membranes and acts on receptors inside the cell

What is a protein hormone?

• Made up of chains of amino acids, water soluble, acts on cell membrane receptors.

What is the functions of the nervous sytems?

• provides fast communciation throughout the body.

• detects change in the internal and external environment using receptors

• electrical impules are sent through neurons to the brain and spinal cord.

• sends quick responses to muscles and glands to maintain balance

What is the function of the endorcine system?

• provides long term regulation using hormones

• hormones are released in the bloodstream and act on target organs

• controls growth, metabolism, etc

What is the function or excretory system?

• removes metabolic waste and regulates body composition.

• kidneys filter blood to remove wastes while reabsorping ions and water.

• maintains internal stability.