lab

In this lab we were supposed to show the bone, joint, muscles, and the neuron. I decided to do the femur, fibula, tibia and the patella.

The supplies I used were construction paper, pipe cleaners, and playdough.


In this picture you see the femur bone with the patella connecting it to the fibula and the tibia.


This picture shows the muscles that are attached the bones. The Quadriceps femoris straightens leg at the knee; raises thigh. The Tibialis anterior turns the foot upward, as when walking on heels. The Extensor digitorum longus raises toes and raises the foot.


The hinge joint is a freely moving joint in which the bones are so articulated as to allow extensive movement in one plane.

These pictures show the neuron with the myelin sheath.

This image is of the sarcomeres contracted it shows how when the mycrofibris of a muscle fiber contracts is shortens them.

The Sarcomeres are in a relaxed state here and not contracted.

lab

During this lab we were supposed to see how many times we could squeeze a ball in twenty seconds with our hand a normal temperature and freezing after soaking our hand in ice water. We were also supposed to see what happened as fatigue set in.










Trial # of Squeezes in 20 seconds 9 More X's
1 66 63
2 50 46
3 63 58
4 61 56
5 54 49
6 53 49
7 51 45
8 49 44
9 49 42
10 45 38
ANALYSIS OF DATA:
1. What are the three changes you observed in a muscle while it is working (contracted)? You could see the muscles moving with each squeeze, after a while the muscles started to burn and it was hard to squeeze the ball.
2. What effect did the cold temperature have on the action of your hand muscles? Explain. When the body gets cold everything starts to slow down. Therefore making it harder and painful at times to continue squeezing the ball.
3. In Figure 3, make a line graph of your results of the fatigue experiment. Be sure to fill in the values on the vertical axis.
Figure 3: Graph of Effect of Fatigue on Muscle Action



4. What effect did fatigue have on the action of your hand muscles? Explain.
Fatigue made it hard for me to continue to squeeze the ball. It also made the numbers of times I could decline.

In this section we learned about:

*calcium and muscle
*calcium and bone
*movement across the joints




The skeletal system is made up of 206 bones, cartilage and fibrous connective tissue. The skeletal system has many different purposes. Some of these are to support the body, protect our organs, allow flexiblity and movement with the help of muscle, it produces red blood cells, and stores fats and minerals.




Cartilage is a connective tissue that is not as strong as bone. It contains collagenous and elastic fibers. Cartilage has no nerves or blood vessels. Therefore making it difficult to heal if injured. There are three different types of cartilage:

Hyaline cartilage - firm and somewhat flexible, it's found at the end of long bones, in the nose, at the end of ribs and in the larynx and trachea

Fibrocartilage - stronger than hyaline cartilage, able to withstand tension and pressure, found in the knee and the vertebrae discs

Elastic cartilage - more flexible than hyaline, found in the ears and epiglottis



Connective Tissues is one of the four types of tissues in the body. Connective tissue is involved in support and structure. There are four types of connective tissue.

Areolar (loose) connective tissue - holds organs and the the top layer of skin together

Adipose tissue - is used for cushioning and energy

Fibrous tissue - forms ligaments and tendons

Reticular tissue - form a soft skeleton to support the lymphoid organs



Muscle



The human body has over 600 muscles in their body. There are three different types of muscle tissue:



Smooth muscle - spindle shaped cells with single nucleus, usually aranged in parallel lines, forming sheets, contraction of smooth muscle is involuntary, does not fatigue easily. They are found in the wall of the bladder, digestive tract, uterus, blood vessels and other internal organs.



Skeletal muscle - tubular fibers that are mulitnucleated, and striated. They run the length of the bone. Movement is voluntary such as the legs and arms.



Cardiac muscle - forms the heart wall and has feature of both the smooth muscle and the skeletal muscle. Fibers are generally uninucleated, striated, tubular, and branched allowing it to interlock at intercalated disks. Muscule contraction is involuntary and rhythmical.


Calcium and Muscle

When muscle fibers are stimulated by axons in the motor neurons to contract the vesicles are filled with the neurotransmitter acetylcholine (ACH). When the nerve impulse arrives at the axon terminal, ach is released. When ach is released it quickly binds to receptors in the sarcolemma. Which then generated impulses that spread over the sacrolemma and down T tubules to the sarcoplasmic reticulum. The release of calcium causes the sarcomere to contract. When calcium ions are released from the sarcoplasmic reticulum, it combines with tropomin causing the tropomyosin threads to shift their position, exposing the binding sites and allowing the myosin to bind to actin.

Calcium and Bone

Calcium plays and important role in the development and maintenance of our bone tissue. Bone tissue is constanlty regenerating itself. Without enough calcium in our body our bones start to show weaknesses. A major condition caused by this is osteoporosis. During osteoporosis men may lose up to 25% of their bone mass and women may lose up to 35% of theirs. Thus leaving them vulnerable to broken bones. While osteoporosis can't be prevented by making sure you are taking in an adequate amount of calcium you can help delay the process.

Joint Movement

Thanks to out joints we are able to bend, twist, turn, wave, rotate, etc the different areas of our body.

The most commonly known joint are the hinge joint and the ball and socket joint.



The hinge joint allows movement to take place in a certain spot. Such as our elbows, knees, wrists, etc. It permits only one type of movement and that is an forward and backward motion.

The ball and socket joint allows us to move our limbs in a circular motion. Such as in our shoulders and hips.


Works Sited:

http://www.polychondritis.com/connectivetissue/Cartilage/WhatisCartilage.html

http://en.wikipedia.org/wiki/Connective_tissue

http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=DMUS,DMUS:2006-49,DMUS:en&q=pictures+muscles

http://www.uoguelph.ca/zoology/devobio/210labs/muscle1.html

Mader Human Biology 10e

Sensory Receptors

Sensory receptors are dendrites that detect stimulation. The exteroceptors detect stimuli from outside the body while the introceptores detect stimulation on the inside of the body. These interoceptors are directly involved with homeostasis.

"The sensory receptors involved in taste and smell contain receptors that bind to specific chemicals. Odor receptors in olfactory receptor neurons, for example, are activated by interacting with molecular structures on the odor molecule. Similarly, taste receptors (gustatory receptors) in taste buds interact with chemicals in food to produce an action potential.

Other receptors such as mechanoreceptors and photoreceptors respond to physical stimuli. For example, photoreceptor cells contain specialized proteins such as rhodopsin to transduce the physical energy in light into electrical signals. Some types of mechanoreceptors fire action potentials when their membranes are physically stretched.

The sensory receptor functions as the first component in a sensory system.

Sensory receptors respond to specific stimulus modalities. The stimulus modality to which a sensory receptor responds is determined by the sensory receptor's adequate stimulus.

The sensory receptor responds to its stimulus modality by initiating sensory transduction. This may be accomplished by a net shift in the initial states of a receptor(see a picture of these putative states [1] with the biophysical description - link [2])."

There are different types of sensory receptors. There is the Chemorceptors that respond to a chemical substance. The pain receptors that respond to damaged tissue. They alert us to possible danger. The photoreceptors respond to light energy. That is why our eyes dilate. The mechnoreceptors are stimulated by mechanical forces which is usually a result of pressure. Thermoreceptors are stimulated by temperature change.

Once the nerve is stimulated it sends a singal to the brain.

Do drugs affect the nervous system?

Yes, Yes and Yes....I can't say it enough. Drugs definetly affect the nervous system. Depending on the type of drug a person is using they will see different results. Not only will it affect the person under the influence but, if they are pregnant it could cause problems to the infant when they are born.

Alot of the "feel good drugs" like coke, crystal, ecstasy deplete the body of dopamine which is a natural chemical we have in our brain. Users of those drugs will feel emotional, depressed and possibly suicidal once the drug leaves their system.

Although most people don't consider alcohol a drug technically it is. Alcohol when abused can be very detrimental to the body and brain over time internal organs will start to show damage. While under the influence of alchol the central nervous system becomes depressed.

Nicotine acts as a stimulant to the central nervous system. The nicotine causes dopamine to be released. Nicotine mimics acetylcholine and increases skeletal muscle activity, heart rate and blood pressure. Long term use of nicotine can cause various types of cancer.

Cocaine/methamphetamine's are also a stimulant to the central nervous system.

Marijuana causes the central nervous system to have a feeling of euphoria, along with altering vision and judgement. Long term use can cause hallucinations, depression, anxiety and paranoia.

The Autonomic System

Blue= parasympathetic
Red= sympathetic

The autonomic system is also in the perepherial nervous system. " The ANS has far reaching effects, including: heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils, micturition - (the discharge of urine), and erection. Whereas most of its actions are involuntary, some ANS functions work in tandem with the conscious mind, such as breathing. The ANS is divided into two limbs, the parasympathetic nervous system which is primarily involved in relaxation, and the sympathetic nervous system which causes the body to become more active as in the "fight or flight" response.

The ANS is a classical term, widely used throughout the scientific and medical community. Its most useful definition could be: the sensory and motor neurons that innervate the viscera. These neurons form reflex arcs that pass through the lower brainstem or medulla oblongata. This explains that when the central nervous system (CNS) is damaged experimentally or by accident above that level, a vegetative life is still possible, whereby cardiovascular, digestive and respiratory functions are adequately regulated."

It is divided into the sympathetic and parympatheic divisions. While their functions are different they do share some similar features. They function automatically and it's usually involuntary. They innervate all internal organs. They utilize two nuerons and one ganglian for each impulse.

The sympathetic division is most usefull during emergency situations. It accelerates the heartrate and dialates the bronchial tube. It inhibits digestion during an emergency situation because that is not considered a priority at the time.

The parasympathetic division includes a few cranial nerves as well as fibers that come from the bottom part of the spinal cord. This division is also known as the "housekeeping division" because it promotes all internal responsed when we are relaxed; ie, contracted pupils, slow heartbeat, etc.

The Peripheral Nervous System

The Peripheral Nervous System lies outside the Central Nervous System and contains the nerves. It is not protected by bones therefore it's vulnerable to toxins and mechanical injuries. It is divided into two systems the somatic system and the autonomic system.

The somatic system nerves serve the skin, skeletal muscles and tendons. It is associated with voluntary control of body movements through the actions of the skeletal muscles and external stimuli.
"The somatic nervous system processes sensory information and controls all voluntary muscular systems within the body, with the exception of reflex arcs.

The basic route of nerve signals within the efferent somatic nervous system involves a sequence that begins in the upper cell bodies of motor neurons (upper motor neurons) within the precentral gyrus (which approximates the primary motor cortex). Stimuli from the precentral gyrus are transmitted from upper motor neurons and down the corticospinal tract, via axons to control skeletal (voluntary) muscles. These stimuli are conveyed from upper motor neurons through the ventral horn of the spinal cord, and across synapses to be received by the sensory receptors of alpha motor neuron (large lower motor neurons) of the brainstem and spinal cord.

Upper motor neurons release a neurotransmitter, acetylcholine, from their axon terminal knobs, which are received by nicotinic receptors of the alpha motor neurons. In turn, alpha motor neurons relay the stimuli received down their axons via the ventral root of the spinal cord. These signals then proceed to the neuromuscular junctions of skeletal muscles.

From there, acetylcholine is released from the axon terminal knobs of alpha motor neurons, and received by postsynaptic receptors (Nicotinic acetylcholine receptors) of muscles, thereby relaying the stimulus to contract muscle fibers." (wikipedia)