#1

A&P 1 Histology Lab #1

Intro discussion for Endocrine

Review important concepts from videos, why we study slides, and a discussion about some misconceptions you have from A&P1 1. Why do we study slides?

Go To U Michigan’s “Monkey Kidney Slide”

#2

Quick Review from Videos - Endocrine glands make hormones. Hormones are chemical messengers that control the activity

of other tissues (SEE NEXT PAGE for discussion) like neurotransmitters did in the Nervous

System chapter.

* They use the bloodstream to get where they need to go.

- When studying the name of hormones, the word "hormone" is often in the name. Please remember that the words "hormone" or "factor" or "peptide" are often interchangeable in the hormone's name, so these are all the same hormone:

Human Growth Hormone Human Growth Factor Human Growth Peptide

- For each gland studied in lab, know:

- Any tissue layers that are named in the “In-Lab Guide”. - 1 or 2 representative hormones from each layer. On the lab practical, you will be asked questions such as “name a hormone produced by this layer”. You will not be asked "name all the hormones made by this gland or layer". That we will saved for lecture. - "Typical" abbreviations: In lab, you may use them when naming a hormone on a lab exam. For example, Human Growth Hormone is commonly abbreviated "hGH". - The CELL NAMES as indicated in this document. You are not responsible for visual ID’ing all cells, so pay attention to the instruction given in the “In-Lab Guide”.

#3 Carl messes with you.

A&P2 is a “re-learning” of many things from A&P1. You think you know some things from A&P1, but trust me….you have some misconceptions. It is not that you do not remember…..you are wrong because you “memorized” definitions. I can think of several terms we just used, and some related terms, that you probably do not understand. How are you going to study what I told you if you do not understand the terms? Example:

Define Tissue layers and “tissue”. Name some.

Define and give examples of a “function”. What do you mean “protect”? Name a tissue that protects. Name 2 more. What does “control the activity of other tissues” mean? What is a “visceral organ”? Review from A&P 1

Tissues, Tissue layers Visceral Organs and Cells “working together” (copy of this can be found on Lab Guide Webpage)

- 4 basic tissue types, each w/ subtypes:

* Epithelial- lining a cavity or surface, covering & secretion.

* Connective - support & attachment.

* Muscle - movement (locomotion & pump).

* Nervous - e- transmission for info & control of other tissues.

- The term 'Visceral organs' is not an exact term. It usually refers to the abdominopelvic and thoracic organs involved in Digestion, Reproduction, Respiration, Excretion.

Each visceral organ is made up of

combinations of 2 or more of these,

arranged in tissue layers:

Typical Visceral Organ: What they do:

(NOTE: not all have these layers; this is just a

starting point)

- The organ will move a substance through

the lumen of the tube, and typically do one of

2 things (or both):

a. Absorb substances from the lumen

into the tissues.

b. Secrete something into the lumen.

Also, the organ needs to provide

protection, especially from harmful

agents within the lumen, and support

and connect the organ to the body wall.

- Each tissue layer will have one or more tissue type. Tissue layers have specific functions. Here is a

pattern we are often going to see:

1. Mucosa: lines the cavity (lumen), and does all the absorbing & secreting in and out of the lumen.

2. Submucosa: connects the mucosa to underlying tissues, contains glands for secreting into the

lumen, and blood vessels for supplying blood flow (see later).

3. Muscularis externa: move substances through the tube (e.g.: peristalsis). 2 layers: longitudinal

and circular.

4. Serosa: Give an outer "shell"

to the organ, connect the tube to

surrounding structures, and (often)

surround the organ in a protective

fluid-filled bag.

However, our slides are often “pieces of the organ”

more

Serosa

#3 Why you hate microscopes: Our brains are easily confused. And cannot always see what is right in front of our faces. When we go to higher magnification, it is as though we are looking out a window as a plane lands.

Trouble is…we start at scanning power, when we should start at high power!

You only recognize the first photo because you are familiar with the last one! You must get to high power so your brain can recognize features. Then, even at low power, you brain can recognize landmarks. See the bridge in the first photo?

Low Power (Scanning power)

Medium Power

High Power

more

Another problem:

Your brain always looks for familiar patterns, even when it shouldn’t.

But I bet you CAN’T NOT SEE IT!

Let’s see how quickly your brain “tells you what you are seeing”, and ignores the obvious, thereby “not letting you see”:

more

Stain on underpass in Chicago

This is NOT the Lion

King:

But, your brain can be taught. Let me teach you. Go to the next page:

What are you looking at? Keep it to yourself! Don’t influence others!

more

This is called a Ghillie suit, made out of cheap material like burlap. Snipers like it because it is so effective, especially in a “laying down” position:

Notice the outline in the grass of the sniper, and the peculiar look on the head, due to the “hat”.

OK, now what are you seeing? Let’s look again (scroll down):

more

Camouflage works because it confuses your brain.

If we stop confusing your brain, and tell it where to look, it stops working (the camouflage, that is)!

How many snipers are in the first photo? Sometimes zooming in with a microscope helps!

Go To U Michigan’s “How to use a microscope”

If time: Go to Anil Seth’s YouTube talk on audio

camouflage

NOW do you see why we use

microscopes?

#3

Slides have more than 1 tissue layer, and many tissues. Put things in their place on a slide! The following is found in the “In-lab guide”, so you can skip it when you get to this:

Have someone from your group go to the slide tray marked “esophagus” and bring back a slide

Look at the accompanying image. You see a thin slice of an esophagus, without stain. Notice that you cannot see much in the way of layers or structures. So we stain them. The staining is different shades, depending on the fat and protein content of the cells and tissues. Staining the slice lets your brain see things much more clearly. Sometimes you will see the whole organ on the slide, especially if it from a mouse or other small animal. If it is from a larger animal, like a human, they will only give you a small piece (see box on image), but making sure you get a representation of all the layers you need to see (if present). Sometimes, if it is an older slide, the stain evaporates, as seen in the image. You should make sure you get the “darkest” slide available in the slide tray! Usually, when I have you look at a slide, I will start by having you simply holding it up to the light and orienting yourself. That way, you know what you are looking at! Use Google Image search:

Pituitary gland slide

Webscope: Pituitary gland slide

Find a landmark game

A

B C D E

F

G

H