Male Structure/Function of Reproduction

Male Reproductive system Structure/Function

Penis - external tube that becomes erect to get sperm close to cervix in the female where the ovum would meet it. This is the male organ of reproduction.

Scrotum - external (outside the body) sac which lowers the temperature of the testes so that they have the best environment for production of sperm (which needs to be a slightly cooler temperature).

Testis - (singular for Testes) gonad of the male. the sperm (gametes) are made here

Epididymis - storage location for sperm found on top of the testis.

Vas Deferens- tube to send sperm from the testis (where they are made) -epididymis - (where they are stored) to the urethra

Urethra - What other system is this a part of??? in reproduction it serves as the exit for semen.

Seminal Vesicle, Cowper's gland, and Prostate Gland - 3 glands which make the liquid portion of semen.
    3 things needed to make the liquid portion:
    1. Liquid for sperm to swim in
    2. Sugar (Fructose) which provides energy for the sperm to swim
    3. Chemical to make female environment habitable for sperm (normally pH is incorrect for 'foreign cells'
Sperm+Liquid= Semen

Reproduction notes!

On Tuesday we went all the way through structure/function of the Reproductive System.

As humans we have 2 versions of the reproductive system. What is reproduction in humans? - Reproduction is carried out by living organisms to continue the species. Can be asexual (what is this?) or sexual (using male and female gametes).

What are gametes? - Gametes are the sex cells of the reproductive systems. Each one contains 1/2 of the genetics from mom and dad. These gametes combine to create a new person!

Female Gamete = Ovum (Ova - plural). Develops/Matures in the ovaries. A female is born with all the immature ova she will ever have.

Male Gamete = Sperm. Only 1 sperm can fertilize an egg. Produced and develops in the testes. Males make sperm through much of their lives.

Sex Organs      Male=Testes                                   Female=Ovaries
Gametes          Male=Sperm                                   Female=Ovum
Sex Hormone  Male=Predominately Testosterone   Female=Predominately Estrogen

What are hormones?  Hormones are chemical messengers that are made in 1 location but used in another location.
Sex hormones are made in the gonads and sent to the whole body. BUT only some parts of the body will respond. Puberty is the brain deciding to make/pick up on these signals. At puberty, testosterone or estrogen are are sent to the body to tell gonads to make mature sperm or ova. These hormones also cause the manifestation of secondary sex characteristics

Male=facial hair, voice changes, muscle mass       Female=hips, breasts, hair

Reproduction.

Here is the video on Reproduction from CrashCourse

What are the main structures Hank discusses?

Nutrition

Today we reviewed nutrition and the Harvard Fat article. What did you learn from it about carbohydrates and in particular refined sugars?  What did it say about fats? saturated vs unsaturated?

Here is a link to the site: Harvard. To the right is a graphic of what is recommended as a Healthy Plate.

In your lab (although we did not do this portion), it asked you to weigh out the amount of sugar in one coke. Here is an image of what that looks like with several types of drinks.










Here is another article by Harvard but this one is on carbs. Why is refined sugar a problem?

Final bits on digestion

We finished up the small intestine and reviewed the rugae of the stomach (these are the folds that expand when food is eaten and help with mechanical digestion in the stomach). Side note: The stomach can actually absorb aspirin and alcohol.


We also discussed how pepsin in the stomach is a positive feedback loop. Pepsin is an enzyme in the stomach that breaks down proteins into "medium size" molecules called peptides (what do you think pepsin's optimal pH is?). These peptides in turn trigger the production of more pepsin thereby speeding up the digestion of the larger protein molecules (Why is this important?).

After we leave the small intestine where food is completely broken down and absorbed (this happens near the end), we move into the colon (or large intestine). The structure of the colon is shorter but with more diameter than the SI. In this organ, water is absorbed into the bloodstream via capillaries. This causes the waste to become bulkier. (why wait until the end to absorb water?). The bile that was provided by the liver to the small intestine, causes the waste to turn brown when the water is taken out.

Why is fiber important?

From the colon we move into the rectum (storage organ for waste, until it can be released) and finally to the anus where waste exits the body.

Can you identify what organs mechanical and/or chemical digestion occurs? What are the enzymes involved in each stage and where are they made?

Enzyme animations link

I would like you to review this website on Enzymes, it will help clarify a few things!

Enzyme Animations

Here are a few images of enzymes to help explain function:

Cheese puffs nutrition label

Tuesday and Calories in your food!

Today we looked at how many calories you need to complete different activities and how to calculate this. Why do we care about needed calories? What does this have to do with our question of the term? What keeps me alive and healthy?

 From your lab:

"You expend energy no matter what you're doing, even when sleeping. Your Resting Metabolic Rate (RMR) is the number of calories you'd burn if you stayed in bed all day - a tempting idea for some of you.  The resting metabolic rate uses the variables of height, weight, age and gender.  This is more accurate than calculating calorie needs based on body weight alone. It omits lean body mass and the ratio of muscle-to-fat a body has.  Of course, you use more energy than your RMR so there are three primary components that make up your body's energy expenditure. Adding these three components together, resting metabolic rate, energy expended during physical activity, and the thermic effect of food is an accurate way of determining how many calories your body requires each day."

Here is the government website on what your 'plate' should look like:

Choosemyplate.gov

We also started looking how to read food labels. What do you need to look for? What is important to note? Here is another great site on how to look at labels and calories.

Homework for Thursday: Finish part D and F of your lab (check VC)

Thursday and Monday -Digestion

Thanks to Mrs. Saxe for going over BMI with you. Here is a site for you to explore more on BMI. You also went over how the liver is involved in digestion.

How is the liver involved - produces bile (an emulsifier) stored in the gall bladder and moved into the small intestine. The bile increases the surface area of fats by mechanical digestion. Here is a website with an animation on bile and fats (Bile site)

We continued on our journey through the digestive system. We are still in the small intestine.
What is the function of the small intestine? = breakdown of food and absorption of simple sugars, amino acids, fatty acids, nucleic acids, vitamins, and minerals?


Pancreas enzymes (amylase, lipase, protease) and: (where are these used?)
DNAse breaks down DNA into nucleic acids (where does the DNA come from in your food?)
Where are the nutrients then absorbed into? The plasma! since there are capillaries within the Villi in the small intestine.

What are villi? Finger like projections that help increase the surface area to increase nutrient absorption into the blood. Villi have capillaries within them.

Villi have microvilli on them - to increase the surface area even more for nutrient absorption.

How does the digested food move through the small intestine?

Monday- Digestion notes!

Monday we delved further into structure and function of the parts of the digestive system.

To start with structure and function, we began with:

Mouth - teeth, tongue, salivary glands. Teeth increase surface area by mechanical digestion, while the tongue moves food to the pharynx. The salivary glands (are they alimentary canal or accessory organs?)  produce saliva which has amylase (what does this break down?) by chemical digestion.

Epiglottis - skin flap made of cartilage that closes off the trachea temporarily when you eat to prevent food from entering.

Pharynx - upper part of the throat. the junction between the alimentary canal and airway.

Esophagus  - muscular tube -transfers food (bolus) to the stomach from the mouth by a series of muscle contractions called peristalsis. tube is closed unless food is inside.

Stomach - muscular sac which has an elastic mucus lining. function - to aid digestion. Mucus lining - helps protect the stomach does not digest itself, lining cells are quickly replaced.
   1. Mechanical - churning of the layers of muscle (which go in different directions).
   2. Chemical - 2 major chemicals involved. a)HCl-breaks down everything. b) Pepsin - breaks down proteins.
We will talk more about Rugae on Thursday!


Small Intestine - muscular tube that contains and moves chyme (liquefied food) where the food is broken down even more and the majority of absorption takes place. We will continue the structure of the SI on Thursday!

Pancreatic Enzymes, made by the pancreas and put into the beginning of the SI
1. Pancreatic Amylase - substrate (what enzyme works on) starches and medium size sugars into the products = Simple Sugars (such as glucose!)
2. Lipase - substrate = fats (lipids) into product = fatty acids (with help from bile (where is this made then stored?)
3. Protease - subsrate = proteins into product = amino acids
4. DNAse - substrate = DNA into product = nucleic acids

Where do the nutrients that are the products absorbed into and by what structure?


Here is a video that may help. (reminder: the enzymes are not discussed in the video, but you should know them!)

More on digestion!

On saturday, we continued to talk about the digestive system. How do we measure the energy in food? Calories (Cal = kilocalories) - measurement of energy in food Calorie definition.
Where is energy stored= in matter!

Why do we need matter?
1. growth
2. tissue repair
3. copy DNA (we have to get some amino acids from other organisms)
Where does the matter go if you lose weight? 
CO2 (exhaled out), waste, water

The basic nutrient categories are listed below
Protein - 4 cal/g
Carbohydrates - 9 cal/g
Fats - 9 cal/g
Nutrients without calories but are necessary
Vitamins/Minerals 0 cal/g
H20 0 cal/g

The 4 stages of digestion
Ingestion - Taking food in involves oral cavity (Salivary Glands, Tongue, Teeth)
Digestion - Breakdown of food into small molecules
         a. Mechanical - Chew/Churn makes pieces smaller - increases surface area!
         (Why is increasing surface area so important??)
         b. Chemical - rearrange atoms so enzymes, chemicals have more surface area to work on!
Absorption - absorbs nutrients/water into blood (which moves them around the body)
Elimination - Release of undigested material (ex. non soluble fiber from plants, and other material (ex. dead cells)


Two 'sections' of the digestive system.
Alimentary Canal - tube made up of several organs where digestion happens. starts at the mouth --> pharynx --> esophagus --> stomach -->small intestine --> large intestine (colon) --> rectum --> anus. Food enters all these organs

Lined by epithelial tissues that secrete mucus which lubricates the channel and in the stomach helps prevent acids from destroying it.

Accessory (or Auxiliary) Organs -  organs that are part of the digestive system (food does NOT enter). These organs secrete enzymes and other digestive juices which are then put into the alimentary canal to aid digestion. (ex = salivary glands and amylase, pancreas, liver, gall bladder, appendix)

Thursday and Digestion!

On Thursday, we went over the two articles you had to read awhile back. Remember when reading these types of articles, you want to look for the claim (What is the hypothesis?) and what is the evidence? Can you determine the experimental design? Homework is to do the gizmo and a case study question.

Here are a few sites with some practice problems for identifying the components of experimental design.

Identifying variables.
SpongeBob and experimental design


Finally we began going over the digestive system by starting with two questions..

How does the digestive system keep you alive? - get food in, get nutrients from food, get waste out!
What other systems does it connect to? - to the circulatory system via absorption in the intestines. Also connected to the nervous system (remember this is all done without you thinking about it!)

Here is one website with a great list of definitions! (you don't need to know all of these though!) Definitions - digestive system.
We started by watching the crash course video. What is the basic makeup of the organs in the digestive system? ("the more complex the animal, the more the digestive system resembles a tube"
Why is maximizing surface area important in the digestive system? - helps get more nutrients out because your enzymes can get to more of the food. (remember think "apple boulder --> apple gravel--> apple sand" = increasing surface area!)

What are enzymes? and What is one enzyme in your saliva (and what does it break down?)