Monthly Archives: September 2011

Lecture 29 – The Science of Blood


Congratulations on remaining steadfast during our lengthy discussion on the skeletal system.  I hope you feel comfortable with the knowledge you have obtained.  We are all at varying levels, so even if this was a review for you I hope it was enjoyable.

Hematology is the science of blood.  There are many issues regarding blood.  Some people faint at the site of it.  The religious beliefs of Jehovah’s Witnesses, forbids them to receive blood transfusions.  Before 1985, blood banks did not have a means of testing blood for contamination.  Therefore many people contracted blood-borne diseases from transfusions received before testing was developed.  Many women suffer heavy menstrual cycles as they age, causing them to seek gynecological treatment for the condition.  (I often think about the Biblical story of the woman with the ‘issue of blood’.  The Bible did not say what her issue was, but I suspect she had heavy periods.  Back then women had to sleep in a tent away from others during their monthly cycles.  That poor lady probably rarely saw the inside of her house.)  You get my point by now, which is that blood makes some people very uncomfortable.

I was always fascinated and intrigued by blood.  My first position in the hospital was in the hematology lab.  I was a medical technician during my junior and senior years of college.  I hated getting up at 4 a.m., since I am a night owl.  But the paycheck was worth it.  I called home to inform my parents that I was rich.  (I think minimum wage was about $6.00 in the mid-80’s and I earned over twice that.)  I worked from 6 a.m.-10 a.m. including weekends.  I scheduled classes from 11 a.m. to 3 p.m.  Some evenings I went back to relieve the full-time people who needed time off.  My manager allowed me to study on the clock and even leave a little early sometimes.  Every morning before class I had to draw as many as 400 vials of blood from patients ranging from the NICU to the psychiatric ward.  Then I had to spin my blood down in a centrifuge and deliver them to the other sections within the clinical lab.  My next technical job before applying to professional school was as a medical technician in the emergency department.  I will never forget vitals and IV’s in the gunshot wound victims in North Philadelphia.  I received plenty of practice setting up successful IV’s in the arms of patients who were addicted to drugs.  By 20-years-old, I was a master.  My undergraduate exposure to the hospital solidified my choice to devote my life to diseases and cures.

No matter what your opinion of blood, it is a unique substance.  What is blood?  Simply stated, it is connective tissue with a fluid matrix.  That matrix is plasma.  Cells, corpuscles, and cell fragments are the formed elements.  Where is blood formed?  The answer depends.  In the fetus, blood is formed in the liver and bone marrow.  In adults blood is formed in bone marrow and lymphatic tissue.  Some white blood cells are formed in the lymphatic tissue, also.  According to the textbooks, children have 3 quarts of blood.  Today’s children are much larger so I question the validity of that measurement.  (We are in science, and are supposed to measure using the scientific system.  You know quarts, cups, and “drops” drove me to run away in the third grade!)  Adults have approximately 5 quarts.

Functions of Blood

1 – Transport formed elements

2 – Transport nutrients and gases (O2 andCO2)

3 – Transport waste

4 – Transfers hormones, enzymes, and buffers (maintain a constant hydrogen ion concentration)  (Endocrinology – we will discuss later)

5 – Help maintain body temperature

We will take a break for now.  Do well with this information!  We just covered a few points today, but do not worry.  This survey may take as many as ten lectures and the details are plentiful.  Appreciate your blood because it has an important job.  The next time you get a minor scape and see that vital life fluid, relax as you cleanse the wound and apply a dressing.

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Lecture 28 – Bone Formation


1 – Intramembranous – develops in the connective tissue in embryo.  (Abbreviation for connective tissue is CT).  For example, the bones of the calvarium develop in connective tissue. Calvarial bones form by direct ossification of mesenchyme, which requires condensation of mesenchymal cells which then proliferate and differentiate into osteoblasts.

Embryology is a branch of science that pertains to the development of am embryo from fertilization of the ovum to the fetus stage.  The more you understand embryology, the more you will understand anatomy.  Much later we will delve into embryology.  Whether you are a 4th year medical student, intern, or attending, a deeper understanding of anatomy will assist in practicing and teaching the art of medicine.

2 – Endochondrial bone formation – cartilage model of skeleton insists that you have to remove cartilage to lay down bone.  Please note:  BONE IS NOT CALCIFIED CARTILAGE.  So, how do we grow bones?  Ossification centers form bone by removing cartilage and replacing with bone.  Bone growth occurs at the epiphyseal disc.  The disc remains the same width, but increases in length.  In the late teens or early 20’s, no new cartilage will form.  It can only be destroyed.  Once the diaphysis meets the epiphysis no disc remains and bone growth will cease.  The text books state that this age is 18 for girls and 20 for boys.

Structural and Functional Unit of Compact Bone

Bone is dynamic.  Internally, the spongy bone is called hemopoietic tissue.  It makes blood cells.  (Note the root hem- in the word.)  Compact bone exists on the surface and blood vessels are parallel to the surface.  The matrix of compact bone is very dense.  If you need a bone marrow sample, a convenient place is the crest of the ilium.  Thin people can feel the prominence easily if they place their hands on their hips.

If we cut a cross section of bone, we have a Haversion System.  Many of these systems exist in the shaft of the bone.  A Haversion canal has an artery and a nerve.  Lamella are concentric rings of bone.  Lacunae are little lakes that have osteocytes inside to maintain the bone.  A canaliculi is a structure that radiates from the vessel to a lacuna.  Volkmann’s Canal is parallel to the surface of the bone and feeds into the artery in the Haversion Canal.  Volkmann’s Canal brings blood into the Haversion System.  We could go much deeper into the Haversion Canal, but will keep it brief for now.  We are very close to our survey of blood.  I enjoy teaching the blood system after the skeletal system in a systems review.  Medical students learn regional anatomy, but that is not possible in a virtual environment.  My medical students, especially those from liberal arts backgrounds appreciate these practical applications.

Basic Arthritis Review

Osteoarthritis –

Destruction of articular cartilage

Triggered by trauma or injury

Extreme pain and immobility

Reduction in viscosity of synovial fluid (stickiness –viscosity – root word is viscous).  I think of how a car will not function properly once the engine oil is old.  The engine oil lubricates the metal parts of a car.  The synovial fluid lubricates our joints.

Rheumatoid Arthritis –

Default in the immune system caused by emotional stress.  (As Mary J. Blige would say, “No more drama!”)  Uncontrolled stress can cause many physical symptoms, such as headaches and fatigue.  Exercise, laugh, pace yourself with your work, and limit negative situations.  I am still learning how to keep a balance between work and regular play time.

Inflammation of synovial membrane, causing an increase in synovial fluid

Extreme pain and immobility

Osteoporosis Review

Loss of bone mass

More frequent in females than males; more frequent in whites than blacks

Prevention – Calcium intake and exercise

Cartilage

Also a type of connective tissue-

Bone is a CT with cells, fibers, calcified matrix, and lots of blood vessels.

The matrix for bone is a hydroxyapatite. (Ca++)10(PO4)6(OH)2

Cartilage has cells, fibers, and a firm, yet pliable matrix.  Cartilage has no blood vessels and take a while to heal when damaged.  Cartilage gets its nutrients by diffusion.

Definition – http://en.wikipedia.org/wiki/Diffusion

Diffusion describes the spread of particles through random motion from regions of higher concentration to regions of lower concentration. The time dependence of the statistical distribution in space is given by the diffusion equation. The concept of diffusion is tied to that of mass transfer driven by a concentration gradient, but diffusion can still occur when there is no concentration gradient (but there will be no net flux). Diffusion is invoked in the social sciences to describe the spread of ideas.

You may also seek information from an old chemistry book if further clarification of diffusion is needed.

The matrix of cartilage is glycoaminoglycans.  Let’s break the word down.  Do you remember our beginning lectures about etymology or word origins?  Glyco- refers to sugar,  amino- refers to protein, and –glycans also refers to sugar.  Basically, this is a protein surrounded by sugar.  (Silly joke!)  These collagenous fibers are strong and are embedded in the matrix.  Supposedly, a steel fiber of the same dimension is not as strong as a collagenous fiber.  These fibers also have a cross-linking, which helps provide strength.

Types and Locations of Cartilage

(You can let out a sigh of relief!  This is the last segment before moving on to our fascinating blood.)

1 – Hyaline cartilage – glassy, shiny appearance (Seen in the butcher shop.  Soup bones have shiny, white cartilage.)  I am left-handed, and quite skilled with a knife in the professional setting, but I am not a carnivore.  (I grew up in the cattle rustling state, and was forced to sit at the table many days because I did not want to eat the animals.)  The whole meat in my kitchen sink idea is too much for me, but I had to let you know that you have seen hyaline cartilage many times while preparing your steak.

Locations:

articular surfaces of joints

costal cartilages (attach ribs)

embryonic skeleton – We were all once hyaline cartilage.  Hyaline cartilage keeps the nose open for breathing.  The nose, larynx, trachea, and bronchi are all held open by hyaline cartilage.

2- Elastic cartilage – matrix has elastic fibers

External ear

Eustacian tube  – connects nasopharynx with the middle ear.  The nasopharynx is posterior to the nasal cavity.

Epiglottis is the opening between vocal cords.  (epi – upon; glottis – vocal cords)

Air must pass through vocal cords to talk.  The leaf-like elastic cartilage (epiglottis) closes to force food into the esophagus.

3 – Fibrocartilage – Lots of collagenous fibers in the matrix of fibrocartilage

Locations –

Intervertebral discs and pubic symphysis (bringing together).

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Lecture 27 – Bones – Lower Extremities – Femur, Tibia, and Fibula


Femur – Larger and heavier than other bones.  Proximally, there is a greater and a lesser trochanter.  (Muscles attach to the greater trochanter.)

Distally, you will find the lateral and medial epicondyles.  The neck of the femur is the most frequent and common site of fracture, especially in older people.  The patella, kneecap is between the condyles.  The patella is sesamoid, or shaped like a sesame seed.  The tendon of the quad surrounds the patella.  In other words, the patella is housed in the tendon of quadricepts femoris.  Its job is to stabilize the knee joint.

The epiphyseal plate is where bones grow.  This bone growth ceases by age 21.  X-rays can assist in identifying age.

The tibia is the weight bearing bone of the lower extremity (medial).  It is triangular shaped.  You can feel the apex of the triangle of the tibia through the skin.  There is no muscle on it.  It is only covered with periosteum, that is filled with nerve fibers.  Do you remember the mischievous children who would kick someone in the shins?  Ouch!

The tibia articulates on the proximal end with the femur and the fibula.  The tibia articulates distally with the ankle bone (talus) and fibula.  The fibula is thin and slender.  (I have shared the silly joke before.  We once had a childcare provider named Fibiola.  She loved my youngest child and held him for hours.  She spoke Portuguese and we did not.  It was hilarious.  She was adorable and came highly recommended by her English-speaking relatives.  We just smiled, drew pictures, and spoke body language.  Needless to say, I will never forget her.  The point is, she was tall and thin, like the fibula.)  Use any mental picture you can use to honestly pass the test.

The protrusion, or medial aspect of the distal tibia, which is the medial malleolus, or hammer.

To Review:

Fibula – long, thin and lateral – not weight bearing, muscle attachments, only.

Proximal articulation – tibia; distally it articulates with the talus.

The lateral malleolus is usually larger and is part of the leg.  Many people think it is part of the ankle.

Tarsal bones (7) true ankle bones

2 largest –        calcaneus – heel bone- the Achilles tendon attaches to it

talus

Metatarsals – sole of the foot – 5

1st is the largest and is weight bearing

The 5th is frequently fractured – the dancer’s fracture – 5th metatarsal

Phalanges – Big toe has 2, just like the thumb.  All others have three.

We should be able to cover my final thoughts on bones in two more sessions.  We will make some brief comments of joints, cartilage, and bone formation.  As promised, we will do an extensive survey of blood before going on to some popular muscles.  Do well with this information.

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Brain Circuitry and the Risks of Casual Sex


Once we learn how the brain works, we will be careful selecting a partner in which to copulate.  (Copulation is the scientific term used for sexual intercourse.  Sex is a sensitive topic, but one of the most popular.  We will discuss this topic in the interest of science and medical research.  Our purpose is to provide the information necessary for making better choices.)  Over half of the marriages in America fail.  When I was growing up, adults always said, “Do not have sex before marriage.”  The discussion was over quickly, without discussing the ramifications of poor choices.  I vowed that in my lectures I would give more information.  I am finding that giving the details to young people compels them to make the best choice.  Plus, we take away the desire to do something simply because it is forbidden.

The research we will be exploring was performed by an evolutionary anthropologist named Helen Fisher.  Professor Fisher notes that casual sex is not always casual.  Our brain is similar to an electrical system in a house; it is intricately connected or ‘wired’.  The brain is more complex and sophisticated than a computer.  We are contemporary and liberated today, and it is common for adults to copulate with someone whom they do not have enough compatibility to love.  But after 6 months of casual sex, extreme attachment has complicated the casual sex.  Have you ever heard a friend say, “How did I fall in love with this guy?”  Women have evolved into creatures who experiment with casual sex very well.  But the consequences still exist no matter how cosmopolitan we have become.

Male love is very intense.  Men fall in love more quickly than women and they love very deeply.  Three out of four people who commit suicide after a romantic relationship has ended are men.  Think about all of the stalkers and murder-suicides we hear about on the news.  Many women know how to heal, get counseling, start networking, and move on.  Examine male and female behavior.  Some men have fewer friends than their female counterparts and thus put more into romantic relationships than women.  (We are careful not to generalize, because we have similarities and differences based on gender.  We cannot all fit into a neat package.)  Men tend not to be as expressive as women.  Many women have tightly woven networks with co-workers, biological sisters, mothers, aunts, sororities, and neighbors.  Despite the negative views of female relationships depicted in all of the new ‘housewife’ shows, girls are very supportive of each other.  There is always a sister-girlfriend around when another girl is in emotional turmoil.

Love ’em and leave ‘em is easier said than done for both sexes.  A girl can be the other woman for a while, but then science kicks in and she falls in love.  The sex drive, romantic love, and attachment are three brain systems that are connected.  Romantic love and the sex drive are very closely connected.  Here’s how the brain works.  When you fall in love, you want to start falling into bed with the person.  Elevated levels of dopamine associated with romantic love can trigger testosterone, the hormone of desire (i.e. sex craving).  But the reverse can also happen.  Testosterone can elevate the activity of dopamine and you can fall madly in love with someone you did not intend.  When people sleep around they run the risk of falling in love with the wrong person, getting married, having children, and eventually getting divorced after the roller coaster ride.

Wait!  There’s more information.  When a woman has an orgasm, levels of oxytocin increase.  When a man has an orgasm, levels of vasopressin increase.  Oxytocin and vasopressin are satisfaction hormones.  They give a sense of peace, security, and unity.  If you have enough of these soothing feelings with even the wrong person, you WILL feel attached to them.

Professor Fisher cautions her audience about the use of antidepressants.  In particular, SSRI’s, or selective serotonin uptake inhibitors have an effect on mood and emotional response.  Antidepressants are needed in managing the mental health of people who cannot get out of bed or are contemplating suicide.  Consult your physician before altering your medication schedule.  Do not take an unauthorized drug holiday to experience satisfying sex.

Serotonin-enhancing medications dull the emotions, but can affect romance and attachment in other ways.  SSRI’s dampen the ability to have orgasms, which is a mechanism of attachment.  Having an orgasm is also a form of assessing a mate.  Thus, if a person is not having an organism with their mate on a regular basis the brain is not being flooded with attachment chemicals.  A woman learns a lot about a man in bed.  For instance, is he a self-centered lover who is only concerned about his satisfaction? Is he patient and affectionate?  Does he understand a woman’s body.  The female orgasm does always happen.  In the past researchers called this a maladaptive trait, but now evolutionary psychologists consider it an adaptive trait because it allows a woman to distinguish between Mr. Right and Mr. Wrong.  So, killing a woman’s capacity to have an orgasm destroys the mechanism by which she can assess her potential partner.  The clitoris has over 8,000 nerves.  The only function is feminine pleasure.  (I am thinking about female genital mutilation, FGM, and its capacity to destroy a woman’s sex life.  I will discuss FGM in another session.)  These nerves become less sensitive when taking SSRI’s.  From the male perspective, seminal fluid contains norepinephrine and dopamine, as well as serotonin, testosterone, and estrogen.  All are affected by antidepressants in a negative way.  When a man does not deposit these substances into the vaginal canal, he is not able to influence a woman’s mood positively.  Thus, he is not able to chemically trick her into liking him!  Professor Fisher likens this to taking a medication that blurs your vision.

Now this is the real birds and bees!  I hope you have enjoyed exploring the physiology of sex and all of the hormones involved.  I hope you share this information with your children and grandchildren.  They need to know the exactly how the body works in order to take care of their body.  Do well with this information.

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No More Myths about Human Sexuality


The Role of the Brain in Human Attraction – We really do not know why we pick certain physical characteristics in our quest for mates, but scientists are getting closer to accurate answers.  They have measured every angle of the human face, the symmetry of the bodies of modern dancers, and crafted formulas from the bodies of exotic dancers.  As far as outward features are concerned, the body type for women that is most desired by men is the hour glass shape.  Women work out to preserve that coveted 10 to 12 inch difference between bust-to-waist and waist-to-hip.  Women most prefer that upside down pyramid shape for men, which includes broad shoulders and a cinched waist.  (Look at how men are depicted in an exaggerated fashion on cartoons.)  Of course, we want a potential mate to possess a positive disposition, but we see the physical attributes before getting to know the personality characteristics.  Psychologist Devindra Singh, from the University of Texas studies the waist to hip ratio as it relates to picking mates.  The scientists at UT have manipulated the numbers of enough hips to develop the desired ratio.  I will spare you all of the statistics.  Now this does men that an apple-shaped man or women will not find love.  We are discussing why we like the mates we like.

For those of you who have siblings, think about their past girlfriends or boyfriends.  You should see some similarities in their choices of mates.  If your brother always dates tall, red-headed girls, that is suggestive that there is rhyme and reason to the laws of attraction.  We have all heard the saying, “Opposites attract.”  This old cliché has scientific basis.  MHC or major histocompatibility complex is a term used in microbiology and immunology.  We are all attracted to people with a particular set of genes, known as HMC.  Most of us prefer an HMC that is dramatically different from our own.  This plays an important part in the development of our immune systems.  A mate with a different HMC will allow us all to have strong and robust offspring.  Have you ever seen a very tall man with a short woman or a man of average height with a tall woman?  I have seen computer guys with an affinity for model types.  Opposites do attract.

Women can be very choosey in finding a partner, because they are being competed for.  In the most primitive sense, women looked for stability and men looked for a mate that could reproduce and send their seed into the next generation.  A woman needs a mate who will stick around after she gives birth.  Humans no longer dwell in caves, but the basic rationale behind selecting a mate is very simple.  We all desire to thrive and survive.  Survival truly belongs to the most fit.

Disclaimer:

I am not here to determine whether or not you subscribe to any Darwinian notions.  However, it is difficult to have a scientific discussion without paying homage to the ideas and philosophies of Charles Darwin.  Let’s set some ground rules.  Evolution simply means a transformation.  The world is constantly evolving or transforming.  Aren’t we different since 9/11?  So, we agree that we have evolved.  I have just saved you an email or a phone call.  You do not have to debate me about my usage of the scientific term ‘evolution’.  (My faith is intact and works very well for me.  Even my spirituality has evolved since becoming an adult.  I certainly do not hold all of the views I held at age 18.)

The goal of these lectures is to explore every angle that science, particularly neurobiology plays in selecting a mate.  Our next discussion will explore how smell can decide who is right for you.  I hope you have fun with this series and apply the scientific facts as you search Match.com or the singles seminar sponsored by your place of worship!

Other topics to explore:

Chemicals contained in saliva (Science is involved in an innocent kiss!)

The brain scans of people madly in love are similar to the mentally ill (Yes, you can be love sick.)

Prostaglandins in sperm (Beware of being promiscuous.  You can fall in love with a man who has nothing in common with you.  Intercourse leads to attraction at the cellular level.  Those sperm cells are crafty.)

Brain scans after a traumatic break-up

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The Science of Sex


We will begin a new series that is designed to assist the general public as well as the scientific community about the chemical messages involved in dating, courtship, and sex.  Our goal is always to share information that will assist in having greater knowledge of self.  In the days of my youth, parents would sit children down and have that dreaded discussion about ‘the birds and the bees’, so to speak.  Those conversations were uncomfortable for parents and children.  In professional school I realized that the average person is not equipped with enough information to give a talk on sex and its physiological ramifications.  My mother ordered me to grab a dictionary when we had our talk.  I admired her for her academic posturing, but I had been drawing anatomically correct pictures of every body part for two years prior to our conversation.  Timing is important, too.  I had also been attempting to grow penicillin by placing crumbled crackers and water in a petri dish.  Conversations about natural body processes are still necessary today and I want everybody to be armed with the right information.

Many parents advise girls not to be promiscuous for spiritual reasons.  Do you know that sperm contains chemical messengers that trick a woman into falling in love?  Chemical messengers are also present in saliva.  How is that for a reason to be careful about choosing someone to kiss?  Spirituality is great!  In combination with science, we can help our youth (and adults) to make better choices.  Television is quite graphic today with sexual overtones in commercials and regular shows.  I am excited about this series on the role of science in sex.  Sex is a popular topic of conversation and we should not get our information from pornography or popular magazines.  I had a candid relationship with my grandmother.  She shared that she had given birth to three children before she experienced an orgasm.  Many researchers have studied the differences between the male and female brain activity during an orgasm.  Since the sexual revolution scientists have ceased to be developmentally arrested in the study of the body.  I have seen doctoral theses on a plethora of subjects.  This series should keep our attention as we continue to cover the detailed review of organs and systems.  It is designed to be tasteful, informative, and based on the most up to date research.

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Lecture 26 – Skeletal System – Pelvic Girdle


I have one final thought about the ulna.  Distally, we find the styloid process for the wrist bones.  (Also called carpal bones; remember, the carpals can carry. This is alliteration from elementary English class.)

The carpus consists of 2 rows of 4 bones in each row.

Metacarpals – Palm – 5 bones.  The heads of the metacarpals are called knuckles.

Phalanges – 3 in fingers and 2 in each thumb.

Pelvic girdle – Pelvis means “basin” and basins carry objects!  This is a simple concept.  The pelvis consists of 3 bones, the ilium, the ischium, and the pubic bone.  All come together at the acetabulum, which means vinegar cup.  The vinegar cup or acetabulum receives the head of the femur.

Ilium

The anterior iliac spine is important for attaching ligaments.

The sacroiliac joint sometimes loosens with age and can produce intense pain.

The ischium is posterior and inferior.  We sit on our ischial tuberosities.  The obturator foramen receives blood vessels and nerves.  The outer part of the foramen is covered with connective tissue.

The pubic bone is the most anterior pelvic bone.  The two pubic bones meet in the middle at the pubic symphysis.  Symphysis means together.  (Think about a musical symphony where many instruments are played together to provide one beautiful sound.  I am sure that you recall my method for learning, which is to utilize any honest techniques to assist your memory.)  Fibrocartilage is located at the pubic symphysis.  This joint loosens during childbirth to allow for the passage of the baby.  Sometimes expectant mothers experience wobbly hips late in the pregnancy, thereby needing to rise from a sitting position slowly.  Sometimes women experience pain at this joint during pregnancy.  The body is highly capable of carrying out its natural functions.

The loosening of the pubic symphysis accounts for one of the distinct differences between women and men.  The male pelvis is narrower, heavier, and deeper.  The pelvis of a woman is wider.  Do well with this information.

 

 

 

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