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Watch this video to learn more about the reflex arc of the corneal reflex. When the right cornea senses a tactile stimulus, what happens to the left eye? Explain your answer.

Watch this video to learn more about newborn reflexes. Newborns have a set of reflexes that are expected to have been crucial to survival before the modern age. These reflexes disappear as the baby grows, as some of them may be unnecessary as they age. The video demonstrates a reflex called the Babinski reflex, in which the foot flexes dorsally and the toes splay out when the sole of the foot is lightly scratched. This is normal for newborns, but it is a sign of reduced myelination of the spinal tract in adults. Why would this reflex be a problem for an adult?

Chapter review

The motor components of the somatic nervous system begin with the frontal lobe of the brain, where the prefrontal cortex is responsible for higher functions such as working memory. The integrative and associate functions of the prefrontal lobe feed into the secondary motor areas, which help plan movements. The premotor cortex and supplemental motor area then feed into the primary motor cortex that initiates movements. Large Betz cells project through the corticobulbar and corticospinal tracts to synapse on lower motor neurons in the brain stem and ventral horn of the spinal cord, respectively. These connections are responsible for generating movements of skeletal muscles.

The extrapyramidal system includes projections from the brain stem and higher centers that influence movement, mostly to maintain balance and posture, as well as to maintain muscle tone. The superior colliculus and red nucleus in the midbrain, the vestibular nuclei in the medulla, and the reticular formation throughout the brain stem each have tracts projecting to the spinal cord in this system. Descending input from the secondary motor cortices, basal nuclei, and cerebellum connect to the origins of these tracts in the brain stem.

All of these motor pathways project to the spinal cord to synapse with motor neurons in the ventral horn of the spinal cord. These lower motor neurons are the cells that connect to skeletal muscle and cause contractions. These neurons project through the spinal nerves to connect to the muscles at neuromuscular junctions. One motor neuron connects to multiple muscle fibers within a target muscle. The number of fibers that are innervated by a single motor neuron varies on the basis of the precision necessary for that muscle and the amount of force necessary for that motor unit. The quadriceps, for example, have many fibers controlled by single motor neurons for powerful contractions that do not need to be precise. The extraocular muscles have only a small number of fibers controlled by each motor neuron because moving the eyes does not require much force, but needs to be very precise.

Reflexes are the simplest circuits within the somatic nervous system. A withdrawal reflex from a painful stimulus only requires the sensory fiber that enters the spinal cord and the motor neuron that projects to a muscle. Antagonist and postural muscles can be coordinated with the withdrawal, making the connections more complex. The simple, single neuronal connection is the basis of somatic reflexes. The corneal reflex is contraction of the orbicularis oculi muscle to blink the eyelid when something touches the surface of the eye. Stretch reflexes maintain a constant length of muscles by causing a contraction of a muscle to compensate for a stretch that can be sensed by a specialized receptor called a muscle spindle.

Watch this video to learn more about the descending motor pathway for the somatic nervous system. The autonomic connections are mentioned, which are covered in another chapter. From this brief video, only some of the descending motor pathway of the somatic nervous system is described. Which division of the pathway is described and which division is left out?

The video only describes the lateral division of the corticospinal tract. The anterior division is omitted.

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Visit this site to read about an elderly woman who starts to lose the ability to control fine movements, such as speech and the movement of limbs. Many of the usual causes were ruled out. It was not a stroke, Parkinson’s disease, diabetes, or thyroid dysfunction. The next most obvious cause was medication, so her pharmacist had to be consulted. The side effect of a drug meant to help her sleep had resulted in changes in motor control. What regions of the nervous system are likely to be the focus of haloperidol side effects?

The movement disorders were similar to those seen in movement disorders of the extrapyramidal system, which would mean the basal nuclei are the most likely source of haloperidol side effects. In fact, haloperidol affects dopamine activity, which is a prominent part of the chemistry of the basal nuclei.

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Watch this video to learn more about the reflex arc of the corneal reflex. When the right cornea senses a tactile stimulus, what happens to the left eye? Explain your answer.

The left eye also blinks. The sensory input from one eye activates the motor response of both eyes so that they both blink.

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Watch this video to learn more about newborn reflexes. Newborns have a set of reflexes that are expected to have been crucial to survival before the modern age. These reflexes disappear as the baby grows, as some of them may be unnecessary as they age. The video demonstrates a reflex called the Babinski reflex, in which the foot flexes dorsally and the toes splay out when the sole of the foot is lightly scratched. This is normal for newborns, but it is a sign of reduced myelination of the spinal tract in adults. Why would this reflex be a problem for an adult?

While walking, the sole of the foot may be scraped or scratched by many things. If the foot still reacted as in the Babinski reflex, an adult might lose their balance while walking.

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Questions & Answers

define homeostasis and explain it's importants
Adusei Reply
define the important life processes of humans
Adusei
how the bone marrow transplantation is done?
Tanveer
what is homeostasis
julie Reply
internal temperature of body
Sanket
Homeostasis is the internal constancy in which your body tries to maintain for optimal cellular functioning. For example, your body tries to maintain an internal body temperature of about 98.6F for optimal functioning of your body.
Carmelo
If a prolonged lost of homeostasis occurs, death of the organism will be the outcome.
Carmelo
Another example of homeostasis is that your body tries to maintain a specific blood sugar level, so that your cells can undergo constant cellular respiration and keep you alive.
Carmelo
homeostasis is the fairly constant internal changes of an environment (your internal environment).The temperature of a body must be kept between the range of 37.5°c
raphael
which tissue is more sensitive
Rit Reply
to what?
Lari
explain types of hypertension
Juli Reply
What is bulbar paralysis?
Roshni Reply
how can make penis larger
Marwat Reply
what is the stimuli initiates the control of erythropoiesis?
Ok Reply
oxygen
Liyungu
Erythropoietin, a hormone synthesized and released by the kidneys stimulate erythropoiesis in red bone marrow. When an Individual loses blood (hemorrhage) and the concentration of RBCs or oxygen decreases, erythropoitein will be released.
Carmelo
how lymph is from
Hafsa Reply
Lymph is essentially interstitial fluid that ends up in the lymphatic vessels that didn't go back into the venules. Lymph is composed of the same components as your blood plasma which contains water, solutes, oxygen, CO2, foreign particles such as toxins, bacteria and viruses.
Carmelo
what is the cause of twins
Clarus
The cause of identical twins is when a single fertilized egg undergo mitosis (splits in two) . As a result, both eggs now have the same genetic information, therefore producing two identical twins.
Carmelo
how structure and function relate to each other?
Garmai
This is a very important rule in Anatomy and Physiology. The structure of a cell, tissue, or organ will tell you a lot about it's function.
Carmelo
For example, simple columnar cells (enterocytes) in the villus present in the duodenum of the small intestine contain microvilli. Microvilli are finger like projections of the cell membrane (produce by the cytoskeleton)that increase the surface area for absorption of nutrients into the enterocytes.
Carmelo
The main role of these enterocytes is to absorb. Therefore, having Microvilli as a structure relates to its function.
Carmelo
@ Carmelo thanks for the answer.
Garmai
welcome
Carmelo
what is anatomy
Kamran Reply
is simply defined as the stody of internal and external structure of human body and the relationships between the body part.
Surajo
Anatomy Is The Study Of The Structure Of The Human body
Dennis
anatomy is the science that deals with the study of the body structure
Vida
what is stress hyperglycaemia and Pathophysiology
amani
Hyperglycemia is the term used when somebody is in a state of high blood sugar levels. For example, after you eat a meal with carbohydrates in it, (post-absorbptive state) your blood is hyperglycemic.
Carmelo
Pathophysiology is the study of how diseases function and cause abnormal functioning in the body. Usually pathophysiology is studied at a molecular/cellular level.
Carmelo
I meant to say absorbptive* state on explanation of hyperglycemia. Usually during post-absorbptive state your blood has low blood sugar levels.
Carmelo
what is sex?
Soumyakanta Reply
Your biological sex is determined by your sex chromosome which is pair number 23. if you have a XX pair then you are a female. if you have XY pair then you are a male.
Carmelo
the sex chromosomes are called as allosome
Tanveer
True, the other 22 pairs are called autosomes :)
Carmelo
why the left hemisphere controls the right side body parts and right hemisphere controls the left side body parts?
Tanveer
because it is like that
Sherin
It has to do with how the neuronal pathway are intertwined to opposites sides of the body I think. A motor output from the left cerebral hemisphere (motor cortex) will end up stimulating your right side of the body.
Carmelo
brother Carmelo don't miander, sex ,it just the state of being a male or female
Liyungu
Your biological sex is tied to your DNA (genetic information). A male have testes and female have ovaries which are reproductive organs is tied to your genetic information (sex chromosome). If an individual feels like it is either a male or female is called gender identity.
Carmelo
thanks our beloved brother Carmelo
Liyungu
that's great learning something everyday
Tasheria
what is anatomy
Rohino
most blood enters the ventricle during what phase?
Tina Reply
rapid ejection
Tanveer
Most of the blood in the heart enters the ventricles during the diastolic phase.
Carmelo
ok
ren
which of the following is the types of personal protective equipment protects mucous membranes?
Garmai
Most (not all) mucous membranes secrete mucus because they contain goblet cells in between the epithelial tissue. Mucus coats the layers of epithelium and traps particles. The epithelial type is either stratified squamous, simple columnar, or pseudostratified columnar in mucous membranes.
Carmelo
Are you a professor Carmelo?
Sherin
No sir, I'm a nursing and biology student as well in university.
Carmelo
smart!
Sherin
thanks!
Carmelo
why the fever occurs if any injury or pain occurs
Tanveer
fever is de best indication to show there is an infection
Kumsah
what is the actual mechanism of fever
Tanveer
correct Tanveer, the normal internal body temperature is 98.6 Fareinheit. When the temperature rises above 100 fareinheit, it is usually an indication of infection.
Carmelo
White blood cells which protect you against foreign antigens become active and release cytokines (pyrogens) during infection which causes the hypothalamus to raise your internal body temperature.
Carmelo
thank you so much.really you are very intelligent.
Tanveer
thank you. you are very intelligent
Tanveer
the mechanism of fever appears to be a defensive reaction by the body against infectious disease. when bacteria or viruses invade the body and cause tissue injury one of de body immune system's responses is to produce pyrogen
Kumsah
Yes, the hypothalamus responds to pyrogens by raising your body temperature. The reason your hypothalamus does this is to stunt the growth and metabolism of whatever is causing the infection (bacteria, virus, fungi protozoa, etc.)
Carmelo
how the kidney transplantation is done
Tanveer
Which university are you studying?
Sherin
karnataka
Tanveer
and all of you ,university
Tanveer
Really so talented
Savita
I was asking Carmelo?
Sherin
Georgia State University.
Carmelo
oh nice! I'm in University of Texas
Sherin
nice!!!
Carmelo
vicious this is chaptare I reading 5day after
Taufik
pleas sir can u teach me
Taufik
not sure, can u help me?
Nichole
I'm in University of Technology, Jamaica
Nichole
why do you not helf me
Taufik
what difference exist between anatomy and physiology?
Collins Reply
Anatomy: study of the structure of the body parts and their relationship to one another
Shana
Physiology: Study of the function of body parts and how they work to carry out life-sustaining activities
Shana
physiology function and anatomy location
Bashir
anatomy refers to the study of the body parts and their relationship to each other while physiology deals with functioning of those body parts
Umutoni
Yes of course.In layman language Anatomy is study of internal organs, whereas physiology is study of how those organs function. Anatomy is is related to how they look their shape size... Physiology is how they work
Juveriya
anotomy dealt with the external and internal stuctural features of body and their constituent physiology deals with the functioning or action of that stucture
Tanveer
Anatomy is the study of the structures (internal and external) of a living organism. Physiology is the study of how the structures of a living organism function often at a molecular and cellular level.
Carmelo
anatomy is the structure of different body parts of human body and physiology is the normal body function of body parts of the human body
Akshay
anatomy is study of structure of the body e.g, system,organ's size shape location and physiology is the study of function of the body eg,eye ball movement , release of hormones , circulation of blood etc
Soumya
thanks
Tammy
thanks guys. I appreciate
Collins
thanks bro
SAGAR
Explain the meaning of life in a scientific manner
Dezni
probably it doesn't have a meaning yet it can be realised by certain signs that have a scientifically defined terms?!!!!
Osama
At least in a scientific manner, scientists have agreed that production and use of cellular energy, as well as growth and reproduction are essential when defining what is alive in a biological sense. For example, viruses are not considered alive because they cannot grow or reproduce by themselves.
Carmelo
this virus issues is being challenged currently.
Osama
what z your conclusion over virus bro?
Liyungu
pipo what is the relationship between T- cells ( specifically T-helper), & all three line of defence mechanism
Liyungu
anatomy is the science that deals with the study of the human structure whilst physiology is a science that covers the function and process of the body structure.
Vida
defien brache of Anatomy
Hamad
anatomy is the study of internal and external body parts while physiology is the science that covers the function and process of the body structure.
Priscillah
what is blood fluid
Adefarasin Reply
what is menstrual cycle
Adefarasin
periodic flow of blood from the female human vigina, after an unfertlized egg has been released from the ovaries
Kobby
the shedding of of the uterine walls,that occurs when fertilization doesn't occur
Kevin
fertilization after occur menstrual cycle
Bashir
it's called menses
Melissa
menses:(menstrual cycle) A monthly shedding of uterine lining and blood. For up to 3 to 7 days every 28 days.
Mel
The menstrual cycle is divided into multiple phases. Menses is the last phase of the cycle when fertilization doesn't occur and endometrium of the uterus shed (stratum functionalis) due to lack of estrogen and progesterone signaling.
Carmelo
The lack of estrogen and progesterone signaling is due to the degeneration of the corpus lueteum when fertilization doesn't occur.
Carmelo
Blood fluid: Blood is composed of blood plasma + formed elements. The blood plasma is 55% of blood volume and it contains 90% of water. It also contains ions, hormones, gases, protein transporters, etc. Blood plasma is also considered extracellular fluid.
Carmelo
The formed elements of blood include RBCs (45-50% of blood), WBCs and Plalets (less than 1% of blood).
Carmelo
Almost forgot, blood plasma also carries nutrients which is obviously very important for survival.
Carmelo
we appreciate bro, our studies are becoming easy & easy
Liyungu
what difference between zink and jesta
Anurag Reply
what and where is the midsagittal
Akpeji Reply
the plane dividing the body longitudinal splitting right and left halves symmetrically
Jacob
sagittal. mid sagittal
Melissa
human body largest organ.....
jasveer Reply
liver
JOY

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Source:  OpenStax, Anatomy & Physiology. OpenStax CNX. Feb 04, 2016 Download for free at http://legacy.cnx.org/content/col11496/1.8
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