Test

1. Differentiate between each part of the nervous system:

a) Central and Peripheral

b) Somatic and Autonomic

2. Describe the structure of a neuron. What is the resting membrane potential of a neuron?

Structure of Neuron

• 

• Dendrites

  • Highly branched projections of cytosol that carry signals towards nerve cell body

• Cell Body (Soma)

  • Contains nucleus and is site of cell’s metabolic reactions and will process inputs from dendrites

• Axon

  • Long, thin extension of cytosol that conducts signals away from nerve cell body - can be bundled together to form nerve fibers

• Axon Terminal

  • Small swelling at end of axon - communicates with next neuron, muscle, or gland by releasing chemical signal into synapse

• Myelin Sheath

  • Schwann cells form tightly wrapped insulated covering over axon of nerve cells - act as electrical insulators due to high lipid content

• Node of Ranvier

  • Regularly occurring gap between sections of myelin sheath along axon - allows electrical impulse to travel faster along axon

Resting Membrane Potential of Neuron

3. Describe how an action potential is generated. Be able to label a graph showing this process.

Description

1. Resting State → Depolarization

Sodium channels open allowing Na+ ions to rush in

Causes depolarization (inside neuron positively charged)

2. Depolarization → Repolarization → Undershoot

Sodium channels close and potassium channels open

K+ ions rush out of neuron so inside of neuron becomes negative once again - repolarization

More negative than -70mV (undershoot - hyperpolarized)

3. Undershoot → Resting State

Ionic distribution is largely reversed via the sodium and potassium pumps so Na+/K+ pump restores resting membrane potential of neuron to -70mV

Graph

4. Describe how an action potential (nerve impulse) travels down a myelinated and unmyelinated neuron.

• Action potential propagates (moves) down axon as wave of depolarization

• think of an exposed vs. covered wire, rubber around the metal controls the electrons on the inside allowing for smoother and quicker movement

5. Discuss the importance of the sodium-potassium pump to maintaining resting membrane potential.

For every 3 Na+ ions pumped out, only 2 K+ ions are pumped in which leads to a net loss of positive charge from inside cell

• makes inside of cell negative in relation to outside

Pump then maintains the resting membrane potential (RMP) at -70mV

6. Describe in detail, the mechanism by which a nerve impulse is sent between neurons.

7. Nerve impulses are all-or-none events, what does this mean? What does threshold potential mean?

This relates to Threshold Potential. Essentially, at -55 mV (Threshold), a neuron has enough energy to open voltage-gated ion channels or fire. It’s all or nothing as if not reached, neuron will not fire (no AP). Threshold reached when combined stimulus from nearby dendrites exceeds minimum level of depolarization

8. Describe in detail the way in which the endocrine system regulates blood sugar levels.

9. Describe the different types of Diabetes and treatment.

10. Describe the function of the male and female reproductive hormones, sex organs, process of gamete formation, as well as the ovarian cycle.

Female Reproductive Hormones

Male Reproductive Hormones

Female Sex Organs

Ovary

• Females have a pair of ovaries

• Eggs (ova) produced and released here

• Estrogens and progestins produced

Oviduct (Fallopian Tube)

• Hollow tube with muscular walls lined with cilia

  • propel egg

• Connects ovary and uterus

  • fertilization occurs here

• Egg travels through oviduct (fallopian tube) to get to uterus

Uterus

• Hollow structure with walls made of smooth muscle

• Fertilized egg (zygote) implants into lining (endometrium)

Cervix

• Lower portion of uterus - cervix

Vagina

• Muscular canal connected to cervix

• At birth, baby passes from the uterus through the vagina to the outside

Male Sex Organs

Testes

• Males have two testes, suspended in a bag-like scrotum

• 125m of seminiferous tubules - spermatogenesis occurs

• Scrotum helps regulate body temperature

Epididymis

• Sperm flows from seminiferous tubules into epididymis (coiled storage tubule attached to surface of each testis)

• Rhythmic muscular contractions of epididymis move sperm into vas deferens

Vas Deferens

• Thick-walled muscular tube that extends through abdominal cavity - sperm travels through until passes out urethra

• Fluid from seminal vesicle & prostate mix with sperm - semen

Female Gamete Formation

Oogenesis - process of producing and releasing eggs

Oocyte - immature egg that only undergone 1st meiotic division

Born with ~1 million oocytes arrested at Prophase I

~380 ovulated before menopause

2nd meiotic division occurs only if oocyte is penetrated by sperm

• mature ovum and polar body formed

Nuclei of ovum and sperm fuse - zygote

Male Gamete Formation

1. 125m of seminiferous tubules in testes

2. Spermatogenesis occurs

3. Sperm flows from seminiferous tubules into epididymis

4. Rhythmic muscular contractions of epididymis move sperm into Vas Deferens

5. Sperm travels through until passes out urethra

6. Fluid from seminal vesicle & prostate mix with sperm - semen

Ovarian Cycle

11. Explain in detail how the immune system works to protect your body from illness and infection

12. What is the function of the digestive system? What organs does it include? What is structure and function of each organ discussed in class? Label.

Function

specialized organs help to break down the food that we eat into nutrients that can then be delivered to the body’s cells

Organs Involved

• teeth

  • small, hard bone structures

  • breaks down food for physical digestion

• salivary glands

  • starts chemical breakdown

• alimentary canal

  • pushes food towards stomach via peristalsis

• epiglottis

  • stops food from entering lungs

• stomach

  • organ that contracts to move food

  • uses muscles as valves

  • chemical breakdown occurs

• liver

  • responsible for detoxification

  • metabolism of nutrients

  • production of bile for digestion

  • storage of glycogen

• pancreas

  • releases various enzymes to further help breakdown food

• gallbladder

  • small, pear-shaped organ located beneath liver

  • stores and concentrates bile produced by the liver

    • releasing it into the small intestine to aid in digestion of fats.

• small intestine

  • is where bile is released into break down fats

  • most absorption of nutrients occurs here

  • has villi to increase surface area

  • capillaries to absorb water-based nutrients

  • lacteals to absorb fat-based nutrients

• large intestine

  • absorption of water, vitamins, and minerals occurs here

  • has billions of E. coli to help with absorption

• rectum

  • removes food waste

Diagram

13. Explain in detail physical digestion, chemical digestion, and absorption.

Physical Digestion

• intended to break down large forms of macromolecules into smaller forms to increase surface area for chemical reactions

• organs involved include: teeth, stomach, gallbladder, liver, small intestine

Chemical Digestion

• intended to break down small macromolecules (carbs, fats, proteins) even further than physical digestion, into its monomers to allow for absorption in the body

• enzymes help speed up the process of these chemical reactions

• organs involved include: salivary glands, stomach, small intestine, liver, pancreas, bile

Absorption

• how the body gets something useful out of food and transports it into the body

• occurs in the small and large intestine

• small intestine absorbs larger molecules like macromolecules via villi

  • villi are hair-like projections that increase surface area for absorption

  • it has capillaries for water-based nutrients and lacteals for fat-based ones

• large intestine absorbs water, vitamins, and minerals via E. coli, the bacteria

14. Describe how food passes through this system.

Imagine an all-in-one food called Seangoop. When ingested:

1. It enters the mouth and begins to physically break down

2. Enzymes in the saliva begin breaking down the fats and carbs into smaller forms

3. It is a ball (bolus) and is swallowed

4. It goes down the esophagus by peristalsis

5. it enters (and it cut off) by the stomach by its valves

6. the acids and enzymes in the stomach begin to chemically breakdown the fats and proteins

7. when it enter the small intestine, the fats are liquified (called “chyme”) and bile is secreted by the duodenum (first section of small intestine)

8. the carbs break down from maltose to glucose, the proteins from short aa chains → amino acids, and fats → glycerol and fatty acid tails

9. the villi in your small intestine begin to absorb the glucose, glycerol+fatty acids, and amino acids

10. the remaining water, vitamins, and minerals of Seangoop are absorbed by the E. coli of the large intestine

11. the food enters your rectum and exits your body by the anus

15. What is the function of the circulatory system? What organs/tissues does it include? What is the structure and function of each organ discussed? Label.

Function

• transports nutrients

• transports urea and other wastes

• transports respiratory gases

• transports hormones

• transports special proteins to fight infection and clot wounds

Organs Involved+Function and Structure

• Blood vessels

  • moves blood form and to heart, lungs and rest of body

• Heart

  • made of cardiac muscle

    • branching and has ability to contract without being stimulated by a nerve (myogenic)

  • 4 chamber muscle responsible for the pumping of blood throughout the body and the lungs

  • made of artery, veins, atriums and ventricles

  • its right side is smaller as it bring blood from the body to the lung to get oxygenated (the lung is close by

  • its left side is larger as it brings blood from the lungs to the body to deliver nutrients

• Blood

  • carries compounds throughout the body needed for it to survive

• Lungs

  • oxygenate deoxygenated blood

Diagram

16. What are components of our blood? What does each do?

• Plasma is about 90% water and 10% dissolved substances (nutrients, vitamins, minerals, antibodies, hormones, clotting proteins, CO2, urea)

• Red blood cells (RBC), also called erythrocytes, and are

  enucleated and biconcave in shape

  • They are filled with hemoglobin, which transports oxygen

• White blood cells (WBC), also called leucocytes and lymphocytes, are slightly larger than RBC and have a nucleus and fight infections

• Platelets, also called thrombocytes, are cell fragments that are involved in forming blood clots

17. Compare the three types of blood vessels.

18. Explain how blood flows through the heart in detail.

1. atria contract

   1. blood flows from atria to ventricles

2. ventricles contract

   1. blood flows from right ventricle to lungs blood flows from left ventricle to aorta (body)

19. Describe heart rate, heartbeat, and blood pressure in detail.

Heart Rate

• Sinoatrial (SA) node is a neuromuscular mass in right atrium that sets heart’s tempo

• Stimulation by sympathetic nerves increases heart rate, while parasympathetic stimulation slows heart rate

• Secretion of adrenaline speeds up heart rate

Heartbeat

Blood Pressure

20. What is the function of the respiratory system? What organs/tissues does it include? What is the structure and function of each organ? Label.

21. Explain how we breathe in detail?

22. Explain how gas exchange occurs in detail?