Directional Terms - human

Here is a handy reference on directional terms used for human anatomy.  I was nice enough to choose the pictures of people with clothes on.  You're welcome.

Here are some specific to the brain, because for humans our brain as we are standing is tilted compared to the way we hold up our heads, like so:

Source on Studyblue

So simply using superior/inferior and anterior/posterior doesn't quite work for how we normally think of orienting the brain, which is why we use dorsal/ventral and rostral/caudal.

Here is a memory aid for this.  I had a hard time keeping dorsal/ventral straight, so this is what helped me.

When I think of dorsal, a shark comes to mind with its iconic dorsal fin on its back or in this case top:

For ventral being the bottom or down, I had to think about stingrays.  They take water in on the top of their bodies and then shoot the water out the bottom over their gills.  So they vent the water out the bottom side of their body.  Hope that helps.

Left image: top/ dorsal side of stingray.  Right image: bottom / ventral side of stingray

There ya go, have fun in anatomy or whatever class brought you to find this blog!

Stay curious.

Respiration, Oxygen, and Hemoglobin

By decreasing pressure inside the thoracic cavity, we are able to inspire air.  By contracting the diaphragm, intercostal muscles, and others, we increase the size of the thoracic cavity, which in turn lowers the pressure to the point that it is lower than the outside air, causing a pressure gradient so the air rushes into the lungs.  To exhale, it is the opposite- relax the muscles, decrease the space in the cavity, which increases the pressure inside until higher than outside, so the air rushes out to where the pressure is lower.

This video is a good summary.  The embedding doesn't work, so you'll have to click the link instead.  Just left the embed on there for the picture. :)

http://youtu.be/V1FAnE31AYs

Partial Pressure
Total Pressure of air can be broken into the partial pressures of all the gases contained in that air.  For instance, if the atmospheric pressure is at 760 mm Hg, and 20% of that is Oxygen gas, 80% Nitrogen gas, then the partial pressure of O₂ would be 20% of 760 = 152 mm Hg.  Partial Pressure of N₂would be 80% of 760 = 608 mm Hg.

This illustrates how increasing the pressure, as in the B picture, causes more gas to diffuse into the liquid.  A simple way to think about it is just that the higher the partial pressure of that gas, the less space it has to bounce around in the air, so more of it will end up in the liquid.

Here's a long video on partial pressure and gases getting into solution, I didn't watch the entire thing yet but it looks like a good detailed explanation for those who feel they could use more information.

Nervous System

The nervous system is divided into Central Nervous System (brain and spinal cord) and Peripheral Nervous System (nerves, ganglia, etc).
Here's a little chart, courtesy of a great Physiology student:

Peripheral Nervous System	Central Nervous System
nerves	tracts
ganglia	nuclei
Schwann cells	oligodendrocytes

Part of the Peripheral Nervous System (PNS) is the involuntary part, consisting of efferent neurons controling visceral organs.  This is called the visceral nervous system, but more commonly known as:
Autonomic Nervous System
Autonomic = Automatic = Involuntary
Sympathetic & Parasympathetic divisions.  Here's a silly little video that shows the functions of each.

Sympathetic Division
Location: Thoracic and Lumbar regions of spinal cord

3 Kinds of pathways

Parasympathetic Division
Location: Brain, and Sacral region of spinal cord

Receptors

This is super fun, talks about the brain, gets deep and slightly philosophical, and mentions reflexes.  It's all about the brain! :)

Cell Organelles

Here are some various drawings of an idealized animal cell, showing all the different types of organelles.  Different artists depict them slightly differently, so looking at many versions should be helpful.  If you click the "source" link under each picture, you will find many great websites with further information.  In some cases this will be necessary to be able to see the image.  My black background is messing some of these up, sorry about that.
Look at these to orient yourself, we will then go into detail on each organelle, and then have some unlabeled cell drawings so you can quiz yourself.  Enjoy!

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Organelles
Here are some closeups! :D

Cell membrane

Here is a good depiction of the various things embedded into a cell's plasma membrane (also referred to as the phospholipid bilayer):

Source

Nucleus
Notice the pores, which is where the mRNA (post-transcription) would emerge to go to a ribosome for translation.

Source

Mitochondria

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Here is a labelled mitochondria.  Please note, Matrix and Cristae will come into play when you learn about metabolism.

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And, here is a really sweet video of a mitochondrion, showing some metabolism processes.  FYI Mitochondrion is singular, Mitochondria is plural.  (Link to the animator's website, for better quality, and links to other really cool videos: http://www.xvivo.net/powering-the-cell-mitochondria/)

Golgi

Source

Cytoskeleton

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Identification Practice

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Source: wikipedia

Key for wikipedia image (includes links to wiki pages of each):
Organelles:
1 Nucleolus
2 Nucleus
3 Ribosomes (little dots)
4 Vesicle
5 Rough endoplasmic reticulum
6 Golgi apparatus
7 Cytoskeleton
8 Smooth endoplasmic reticulum
9 Mitochondria
10 Vacuole
11 Cytosol
12 Lysosome
13 Centrioles within Centrosome
14 Cell membrane

The end

Human Anatomy Study Resources

Here is a collection of study resources for students of Human Anatomy.  Nothing special, I just did some Google searches and have compiled a handy list for you.  Best wishes on your studies!

Bones & Joints
Multiple choice bony landmark practice, by placing labels on the appropriate spots on the diagram.  Explore the rest of the website for other good study helps.
http://highered.mcgraw-hill.com/sites/0072919329/student_view0/chapter7/labeling_exercises.html

Bony landmark practice, type in answers and get them checked (note this program does not add the correct parent terms such as "greater tubercle of the humerus", so remember to say/ think them to yourself to avoid bad habits!)
http://www.getbodysmart.com/ap/skeletalsystem/skeleton/menu/menu.html

Muscles
This actually has bones, joints, muscles, and more.  If you get to a view of a region of the body you can look at the bones, muscles, blood vessels, and nerves for that region with one click.
http://www.innerbody.com/htm/body.html

Some pertinent posts on Anatomy/ Physiology from this blog:

Brain Anatomy & Function

http://biogeonerd.blogspot.com/2012/10/brain.html

Neurons

http://biogeonerd.blogspot.com/2012/10/neurons.html

Action Potentials

http://biogeonerd.blogspot.com/2012/02/action-potentials-what-make-your-brain.html

Hormones:

http://biogeonerd.blogspot.com/2012/04/endocrinology-hormones.html

Giant Pacific Octopus

The Giant Pacific Octopus is an amazing animal.  Here is the internal anatomy:

Source - Hatfield Marine Science Center

To watch an octopus in action, HMSC's Octo Cam:
http://hmsc.oregonstate.edu/visitor/octocam

A talk on Octopus Day that is on my list to watch

My favorite new website on cephalopods, which I have yet to spend the hours and days necessary to give justice to:

Cephalove

http://cephalove.southernfriedscience.com/

Muscle Contraction

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Brain Anatomy and Functions

Let's talk about the most amazing organ in the most complex organism on the planet, shall we? :)

Here is a basic orientation:

Brain Stem
The most ancient ("primitive") part of the brain is the brain stem.  This part of your brain is responsible for basic functions to keep you alive.  Includes the Medulla oblongata, Pons, and Midbrain.  First a look at the parts:

Source

Here is a view of a frontal slice through the human brain stem:

1- Cerebrum, 2- thalamus, 3-midbrain, 4- pons, 5- medulla oblongata, 6- spinal cord (Source)

Now a look at each part and the centers each contains that help keep you alive in-the-moment.  Things that could kill you in a matter of seconds or minutes if they don't work properly are controlled here.  We'll start with the most inferior part and move up.

Medulla Oblongota

Control centers of Medulla:

• Vasomotor- regulate blood pressure
• Cardiac center - controls heart rate, strength of contraction
• Respiratory center - controls respiratory muscles, is sensitive to pH (so it can respond by increasing or decreasing respiratory rate which will bring the body back into homeostasis as far as pH)
• Respiratory reflexes - vomiting, swallowing, coughing, sneezing

Mnemonic from Physiology student - "programming your VCR makes you vomit"

Another cool thing that happens in the medulla:

Source

• Decussation of fiber tracts - decussation is a fancy scientific word for swapping.  As you all know, the right side of the brain controls the left side of the body, and vice verse.  The medulla is where the nerve fibers cross over.  (Also referred to as "decussation of pyramids".)
  

  

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Pons

• Pathway between spinal cord and brain
• Fine control of respiration

Inferior view (looking up at bottom of brain) showing the Pons (Wikipedia)

Mesencephalon (midbrain)

• Conduction pathway between cerebral hemispheres
• Reflexes based on visual stimuli (moves head and eyes to protect them from being hit or poked)

That is the brain stem.  Next we will continue superiorly.

Thalamus
Paired organ at top of brain stem, see picture below

Thalamus is the purple part.  Detailed anatomy of brain stem if you want that info. (Source)

•  General sensations of pain, heat, cold, pressure (can't pinpoint location or intensity)

• Sensory Gatekeeper - pathway between cerebral cortex and sensory/somatic systems.  Shuts out some sensory info to allow for greater focus on important things.  So it takes in all that general info and filters out what's not important (such as the sensation of your clothes touching your skin so stuff like that doesn't become distracting)

Reticular Activating System
Housed in the brainstem and thalamus is the Reticular Activating System, shown below in red.
 

reticularactivatingsystem.org

This system controls your waking state and alertness, sending signals to the cerebral cortex to keep you awake and alert.  This allows you to direct your attention to specific events.  It also holds back sensory info at other times to allow you to sleep, and controls your circadian rhythms (sleep-wake transition).  In fact, if I understand correctly, the RAS has an inhibatory affect on the part of the brain that contributes to sleepiness - the Preoptic Area (POA) of the Hypothalamus.  Likewise, the POA can inhibit the RAS when it's time to sleep.  Pretty cool.
An even more cool fact - this alertness center is very active when awake, and is suppressed during deep sleep, but during REM sleep when you are dreaming, the RAS is just as active as when you are awake! :)

Hypothalamus
The inferior part (floor) of the thalamus.  See picture above, the purple front section on left picture.  Also, the picture below gives a more general orientation.  Here are its functions.

Source

•  Manager of the Autonomic Nervous System

• Rage & aggression
• Hunger & satiety
• Fluid osmolarity
• Thirst center
• Anti-diuretic hormone (ADH)
• Body temp
• Regulates the Anterior Pituitary Gland, which affects:
• Growth
• Sexual Function
• Lactation (breast feeding), regulated by oxytocin
• Thyroid function
• Stress, regulated by cortisol

Here's a more detailed diagram of the hypothalamus:

Source

Cerebellum

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The motor integrating center - makes last-minute fine tuning adjustments to motor activities, controlling coordination.
Tells "how far, how fast, and when to put the brakes on"
Sobriety tests are really testing the functionality of the cerebellum.  Depends on sight and proprioception (info on what your body position actually is right now) input.  Prevents dysmetria and past-pointing.  (Dysmetria = missing the mark; past-pointing = moving beyond the mark.)

Source

The cerebellum processes input from other areas of the brain, spinal cord and sensory receptors to provide precise timing for coordinated, smooth movements of the skeletal muscular system. A stroke affecting the cerebellum may cause dizziness, nausea, balance and coordination problems.

Cerebrum

Source

Basal Ganglia/ Basal Nuclei
Trains the brain to do fine motor activities
Suppresses unwanted movement
Initiates trained complex movement patterns
Lesion in this area causes Parkinson's disease

Source

Limbic System
Includes parts surrounding the brain stem: cerebral cortex, basal nuclei, thalamus, and hypothalamus

Source

Responsible for "fight or flight" type of survival, and species survival instincts:

• aggression
• fear
• feeding
• sexual behavior
• motivation

Cortices of the Brain

Primary Motor Cortex
Voluntary contraction of skeletal muscle

Premotor Cortex
Stereotyped movements - "computer programmer" for repeatedly used actions
*Broca's Area
Controls muscles responsible for speech - only on the left side of the brain

Somatosensory Cortex
Pinpoints location and intensity of temperature, touch, pressure, and pain (general sensations of these come from thalamus, then are passed on here to get more details)
Proprioception

Primary Visual Cortex
Vision
Primary Auditory Cortex
Hearing
Olfactory Cortex
Smell
Gustatory Cortex
Taste

Parietal-Temporal-Occipital Association Cortex
Interprets primary sensations from somatic, auditory, and visual areas
*Wernicke's area
Allows for interpretation/ understanding of language (both written and spoken)


Prefrontal Association Cortex
Planning for voluntary activities
Perceiving consequences of future actions
Responsible for personality traits 
Teen drinking impairs the development in this area

For additional information related to the brain, see these other posts:

Action Potentials

Action Potentials Up Close

Neurons

Neuroglia

 Brain Food: Nutrition for Learning & Memory

Nervous System