bio 342 comprehensive sharc

What is tonicity?

The ability of a solution to cause a cell to shrink or swell.

What happens to cells in a hypertonic solution?

Cells shrink as water leaves the cell.

What happens to cells in a hypotonic solution?

Cells burst as water enters the cell.

What type of solute does water movement depend on?

Non-penetrating solutes.

What is the difference between diffusion and facilitated diffusion?

Diffusion does not require a protein, while facilitated diffusion requires a transmembrane protein.

What is active transport?

Active transport requires ATP and moves substances against their gradient.

What is hydrolysis?

Breaking down of substances using water.

Why do you need O2?

To create ATP.

How is O2 transported in the blood?

Mostly by hemoglobin and sometimes by myoglobin.

Why do we need to get rid of CO2?

CO2 buildup causes excess H+ in the blood, lowering pH and causing metabolic acidosis.

How is pH measured?

By the amount of H+ in the blood.

Which organs help maintain pH homeostasis?

The kidneys and lungs.

What determines the resting potential?

The distribution of sodium(outside) and potassium(inside cell) ions.

What does the Na+/K+ ATPase do?

It moves 3 Na+ out and 2 K+ in, maintaining concentration gradients.

Where is the pacemaker of the heart located? what does it determine

In the sinoatrial (SA) node. determines resting HR

How is heart rate regulated by the sympathetic nervous system?

By releasing NE & EPI on beta adrenergic receptors, increasing Na+ and Ca2+ influx, which increases HR.

How is heart rate regulated by the parasympathetic nervous system?

By releasing ACh on muscarinic receptors, increasing K+ efflux and decreasing Ca2+ influx, which decreases HR.

What is the pathway of blood flow through the heart?

Oxygenated blood enters left atrium → left AV valve → left ventricle → aortic semilunar valve → aorta → systemic circulation → deoxygenated blood in vena cava(SVC & IVC) → right atrium → tricuspid valve → right ventricle → pulmonary semilunar valve → pulmonary trunk → pulmonary arteries

Why do we need valves in the heart?

To prevent backflow and ensure unidirectional flow of blood.

Which hormones are involved in calcium homeostasis?

Parathyroid hormone, calcitriol, and calcitonin.

Why is calcium the most important ion?

It is needed for muscle contraction, heart depolarization, bone building, and neurotransmitter release.

What is different about the pacemaker potential?

It has no true rest, is less permeable to K+, and more permeable to Na+.

What neurotransmitters are released by the sympathetic nervous system?

NE (postganglionic) and EPI (adrenal).

How is CO2 transported to the lungs?

As bicarbonate, bound to proteins, and a small amount dissolved in plasma.

Which organelle makes ATP?

Mitochondria.

What is the function of myelin?

It acts as an electrical insulator that increases the speed of action potentials.

Where are all blood cells made?

In the bone marrow.

Where is acetylcholine stimulatory?

At skeletal muscle, binding to nicotinic receptors.

Where is acetylcholine inhibitory?

In the heart, binding to muscarinic receptors.

How is an action potential initiated?

By depolarization to threshold, activating Na+ channels.

What ions are involved in action potential?

Sodium (Na+) and potassium (K+).

What is needed for muscle contraction?

Ca2+, ATP, and ACh.

What binds to vesicles and causes the release of ACh?

Ca2+

What does ACh bind to on the motor end plate?

Nicotinic receptors

What is required for troponin to move tropomyosin off the myosin binding site?

Ca2+

What is needed for the power stroke to happen?

ATP

What happens when ATP binds to myosin?

Myosin detaches and hydrolyzes ATP, activating it to bind to actin and cause contraction.

Define hydrophilic.

Likes water.

Define hydrophobic.

Doesn't like water.

Which hormones are involved in glucose homeostasis?

Insulin and glucagon.

What is calcitriol?

A steroid hormone released when there is too little Ca2+.

Where is calcitriol released from?

The kidneys.

What is the function of albumin?

Helps maintain blood colloid osmotic pressure and acts as a carrier protein for steroid and thyroid hormones.

What is colloid osmotic pressure?

Pressure due to blood proteins like albumin.

How does colloid osmotic pressure affect filtration?

It opposes GFR; when COP increases, GFR decreases.

How is blood pressure regulated?

Through the baroreceptor reflex and changes in vessel radius.

How does resistance affect blood pressure?

Small changes in radius lead to big changes in flow and pressure.

How is blood flow to tissues regulated?

By vasoconstriction and vasodilation.

What are local vasoconstrictors?

EPI and NE.

What is AngII?

A potent vasoconstrictor.

What are vasodilators?

ANP, EPI, NO, low O2, high K+, CO2, H+.

What factors determine MAP?

BV, CO(SV & HR), and resistance.

How does increased BV affect blood pressure?

It increases blood pressure.

What is the second messenger system?

A system where a hormone binds to a cell surface receptor, causing a change that leads to the synthesis of a second messenger.

What is the most common second messenger?

cAMP.

What are the actions of thyroid hormones?

Increase metabolic rate and protein synthesis, stimulate glycogenolysis and gluconeogenesis, increases lipolysis, decreases lipogenesis, increases respiration rate, increases HR

What are the stimuli for the release of thyroid hormones?

Cold temperature, low TSH, pregnancy, high altitude, hypoglycemia, low TH.

What are the tropic actions of growth hormone?

Stimulates growth of bone and muscle; cells increase amino acid uptake

What is a tropic hormone?

Hormones that lead to the release of other hormones.

Which structures bypass the lungs in fetal circulation?

Foramen ovale and ductus arteriosus.

What carries oxygenated blood in fetal circulation?

Umbilical veins.

What carries deoxygenated blood in fetal circulation?

Umbilical arteries.

What is negative feedback?

A process that returns a regulated variable to its normal value.

How do ions cross the plasma membrane?

Through facilitated diffusion.

Where would Na+ go if given the choice?

From outside to inside the cell.

Where would K+ go if given the choice?

From inside to outside the cell.

How can you get large substances into a cell?

Through active transport/endocytosis.

How do the kidneys help regulate pH homeostasis?

By excreting H+ during acidosis and retaining H+ during alkalosis.

Which hormones are released by the kidneys?

Erythropoietin, calcitriol, and renin.

Define metabolic acidosis.

Low pH caused by high H+, ketoacids, or kidney disease.

How can metabolic acidosis be fixed?

By hyperventilating and kidneys excreting H+.

Define respiratory alkalosis.

High pH caused by hyperventilation.

How can respiratory alkalosis be fixed?

By kidneys or breathing into a bag.

How is breathing regulated?

Inhalation is active, exhalation is passive.

What is the RAAS system?

Renin-Angiotensin-Aldosterone System.

When is the RAAS system activated?

By low blood pressure sensed by the juxtaglomerular apparatus.

What does ADH do?

Helps maintain water homeostasis by decreasing urine production.

Which structures bypass the liver in fetal circulation?

ductus venosus

What is the process of the RAAS?

Renin converts angiotensinogen to Ang I and ACE converts Ang I to Ang II

What does Ang II do?

causes vasoconstriction, the release of ADH from the hypothalamus(keep water) and hypothalamus to cause feeling of thirst, aldosterone to be released from the adrenal cortex, decreases GFR

What are the non-tropic effects of growth hormone?

lipolysis @ adipose tissue, gluconeogenesis, glycogenolysis

which hormones use second messenger system?

hydrophilic/peptide hormones and some steroid hormone

What is step 1 of an action potential?

depolarization to threshold (-55mV)

What is step 2 of an action potential?

activation of Na+ channels = once reach threshold, VG Na+ channels open, rapid depolarization. Na+ ions rush into cytoplasm

What is step 3 of an action potential?

inactivation of Na+ channels, activation of K+ channels. VG Na+ channels close. VG K+ channels are now open= K+ rushes out, Repolarization begins

What is step 4 of an action potential?

return to normal permeability. K+ channels begin to close slowly. Membrane is briefly hyperpolarized to -90mV. Na+/K+ ATPase helps rest back to rest