Biological basis of behavior: Nervous system

Structure of the Nervous System (https://www.khanacademy.org/test-prep/mcat/behavior)

Anatomy of the Nervous system 
(http://kidshealth.org/parent/general/body_basics/brain_nervous_syst
em.html)

03/29/16

The endocrine system includes those organs of the body which produce hormones. It helps to regulate metabolism, growth and development, tissue function, and plays a part also in mood. The field of medicine that deals with disorders of endocrine glands is endocrinology.

In physiology, the endocrine system is a system of glands, each of which secretes a type of hormone directly into the bloodstream to regulate the body.

The endocrine system is in contrast to the exocrine system, which secretes its chemicals using ducts. The endocrine system is an information signal system like the nervous system, yet its effects and mechanism are different.

The endocrine system's effects are slow to start, and long-lasting in their response. The nervous system sends information quickly, and responses are generally short lived. Hormones are complex chemicals released from endocrine tissue into the bloodstream where they travel to target tissues and trigger a response.

Features of endocrine glands are, in general, they have no ducts, they have a good blood supply, and usually they have vacuoles or granules inside their cells, storing their hormones.

 The nervous system and the endocrine system are inter-related.

Even though both are related, they’re both pretty unique.

The Nervous System	The Endocrine System
It is faster. It takes milliseconds to process.	It is slower. It takes days to process.
The effects run out easily.	The effects are lasting.

02/29/15

Modern Ways of Studying the Brain
There are many ways of studying the brain, and each of these methods will show how they relate to each other.
Brain Structure		Brain Function
CAT Scans Computerized Axial Tomography	This method uses an X-ray to create images of the brain. It’s useful for finding abnormal bleeding, swellings, and tumors.	EEG(electroencephalography)	It measures the electrical activities of the neurons that the brain produces. It is useful for reading electrical patterns of the brain and telling cognitive functions.
MRI(Magnetic Resonance Tomography)	It uses a magnetic field to align the atoms of the brain in a certain direction. It then disrupts the atoms using a radio wave, and revert it back to its original formation and make them emit a signal that creates a detailed image of the brain.	MEG(magneto encephalography)	It records magnetic fields produced by the electrical currents of the brain.
	FMRI(Functional Magnetic Resonance Imaging)
	A Combination of the two methods	It creates a detailed image of the brain. And read what parts of the brain are active
	PET(Positron Emission Tomography)scan
	Another Combination of the two methods	It reads what parts of the brain are active. But it doesn’t show a detailed image of the brain, it shows more electrical brain patterns and can record more about brain function.

11/17/15

Lesion studies and experimental ablation

Lesion studies and experimental ablation is a method of deliberately destroying brain tissue or making brain lesions to cause injuries. This means, that the brain is literally being damaged inside a live test subject to see the changes of the subject’s behavior after its brain is damaged. This type of research is only done on lab rats or other test animals.

Performing Experimental Ablation

Surgical removal	Damaging or severing an exact part of the brain then removing it using a surgical scalpel or sucking it out with a machine to be observed.
Radio frequency lesions	Destroying the surface and the depths of the brain by inserting an wire without an insulated tip to an exact part of the brain, then passing a high frequency current through the wire and into the brain. The heat and pressure of the wire destroys neurons. Then the wire is removed and so does the brain.
Neurochemical Lesion	Causing an influx to several neurons and brain sections and kills it using chemicals like Kanic Acid or Oxidopamine.

11/10/15

Early methods of studying the brain
Back then, studying the brain was quite limited. People in the past use different methods and theories in order to study it. But despite the things they do, it helped expand our knowledge about the brain.
Methods:
Wait for someone to die:	This method helped the people expand their knowledge about the structures of the brain.
Waiting until something went horribly wrong: Like insanity or brain injuries.	This method is to find any injury inside the brain of a live person and study its effects of the brain.
Back then, studying the brain needs to have an autopsy to the brain. Which means that doctors and scientist have to wait until someone dies before they can study it.	One of the examples of the ones who had their brains injured is Phineas Gage, who had an iron bar pierce through his head. The effects on his brain changed much of his personality. The effects that profoundly changed his personality were: Before the accident After the accident Hard-working Violent Well-mannered Vulgar Responsible Unpredictable Kind Angry But Gage’s effects on his brain expanded the knowledge of Cerebral localization or the functions of specific areas of the brain.
	Another example is George Broca’s patient “Tan”. Patient “Tan” lost the ability to talk except for the word “tan”. He found out that tan’s left frontal lobe that caused the damage. This results the term of Broca’s area and Broca’s aphasia.

05.14.15

Nervous System

• Developing Nervous System
• Fore Brain: Cerebrum
• Mid Brain:  Mid Brain
• Hind Brain: Brain

• Central Nervous system
• Brain:The master controller of the body.
• Cerebrum: Has Left and Right Cerebral Hemispheres
• Cerebelum:
• Brain Stem:
• Mid Brain
• Pons
• Medulla
• Spinal Cord:
• Peripheral Nervous system
• 05.21.15
• Nerves:A message structure that goes all over the body
• Cranial Nerves: Nerves that come out of the brain to carry information.
• Spinal nerves: Nerves that pass through the spine and delivers messages to the periphery.
• Ganglea: Attached to nerves and contain the "Somas" of nerves. 
• Somas: When carries information to the central nervous system, it becomes affarent neurons.
• Affeirent Neurons: Carries information into the central nervous system 
• Effarent Neurons: Carries information to the peripheral nervous system.

05/26/15
Functions of the nervous system

Functions: Divided into two parts:

• Basic Function
• Form the central nervous system
• Brain
• Spinal Cords
• Form the central nervous system
• Nerves
• Cranial Nerves: Perform in the head.
• Spinal Nerves: Perform in the rest in the body.   

• Motor: Controls the skeletal muscle and results movement and pose.
• Sensory: All detectable senses in the nervous system.
• Automatic: Reflexes and involuntary functions.
• Complex Function
• Cognition: Thinking,learning and language
• Emotion: Feelings
• Consciousness: The awareness and control of one's action

Syndromes: Pattern of abnormalities in Nervous system functions. Caused by neurological or psychiatric disorders.  

06/02/15

• Motor Unit: Is made up of two parts.
• Lower Motor neurons
• Carries information away from the Central Nervous System and controls skeletal muscles. 
• Lower motor neurons fires a potential action to activate itself without messing up by contacting the skeletal muscles through the synapses then to the neuro-muscular junction then tells the skeletal muscles what to contract.  

06/09/15

• Peripheral somatosensation: Composed of five different senses.
• Position Sense: 
• Position of body parts relative to each other, can sense each other without the accompaniment of sight.  
• Vibration sense: 
• Used to feel vibrations from anything that is vibrating.
• Touch: 
• Pain:
• Temperature: 
• Receptors in the Peripheral somatosensation:
• Mechano Receptors: Senses and controls:
  • Position Sense 
  • Vibration sense:
  • 
    
  • Touch: 
   
• Somatosensory Receptors: Controls and senses Technoqtious stimuli and create. 
• Nociceptors: Can sense one of the Technoqtious stimuli sensation like:
• Pain
• Thermal Receptors: Senses one of the Technoqtious stimuli sensation like:
• Temperature

Peripheral somatosensations sends back information into the peripheral nervous system and detects the specific stimuli. 

 

06.23.15

 Reflex - formed by the nervous system, Reflexes can response without the involvement of consciousness. 

• Afferent Stimulus - Sends reflexes into the central nervous system.  
• Efferent Stimulus - Sends reflexes out of the central nervous system. 

 Reflexes can detect muscle stretch and cause your leg to jerk. These are called Muscle spindles. Muscle spindle have neuron axon that can detect the stretch and sends reflexes into the central nervous system. They can make afferent somatosensory neurons that can form exiratory synapse and sends it back to the muscle stretch.

06/29/15
Gray and White Matter:

• Gray Matter
• Contain most of the Neuron-somas. Grey matter, which has a pinkish-grey color in the living brain, contains the cell bodies, dendrites and axon terminals of neurons, so it is where all synapses are. White matter is made of axons connecting different parts of grey matter to each other.

• White Matter
• Contain most of the Myelenated Axons.

Gray and white matter got their names because their pinkish color becomes gray or white if they are removed from the body.

Gray and White matter have different distributions from the brain to the body. They have different sections throughout the spinal cord. Neuron-somas are located inside each spinal cord sections while Myelenated Axons are located, not at the outside but at least the outer layer of the spinal section. The Brain contains grey matter on it's outside layer called cortex. The Cortex covers the cerebrum and cerebelum that make up the cerebral and cereberal cortex. And the White matter on the inside are called nuclei. They contain collections of axons that travel into different areas. The specific paths that axons travel throughout the nervous system are called tracts. Tracts are mostly participating in the central nervous system then mostly goes back to the cerebrum.

07/28/15
Upper Motor Neurons:

Originated in the motor region of the Cerebral Cortex. They control the lower motor neurons. They mainly control the limbs and the trunk. They control the lower motor somas and send down information to the skeletal muscle cells and tell them when to contract.The primary motor cortex or precentral gyrus, is one of the most important areas in the frontal lobe. The precentral gyrus is the most posterior gyrus of the frontal lobe and it lies anterior to the central sulcus. The pyramidal cells of the precentral gyrus are also called upper motor neurons. The fibers of the upper motor neurons project out of the precentral gyrus ending in the brainstem, where they will decussate (intersect) within the lower medulla oblongata to form the lateral corticospinal tract on each side of the spinal cord. The fibers that do not decussate will pass through the medulla and continue on to form the anterior corticospinal tracts. The upper motor neuron descends in the spinal cord to the level of the appropriate spinal nerve root. At this point, the upper motor neuron synapses with the lower motor neuron, each of whose axons innervate a fiber of skeletal muscle.

08/04/15
Somasensory Tracts consists of these tracts:

• Position
• Position receptors are commonly stated that they are found in the arm. They enter spinal nerves in order to send information into the spinal cord. 
• Vibration 
• Vibration receptors send information from the cranial nerves or any part of the body then goes through spinal nerves in order to reach the brain stem.
• Fine touch sense
• Neuron axons carry the information from these receptors in order to reach the brain stem. They usually travel from the other side of the spinal cord to the brain stem then sends information to the deeper part of the cerebrum.
• Pain
• Noxious stimuli detected by pain receptors travel through the nerves until it reaches the spinal cord and delivers the information to the central nervous system.
• Temperature
• These receptors travel through the nerves until it reaches the spinal cord and delivers the information to the central nervous system. Temperature receptors send information from the cranial nerves or any part of the body then goes through spinal nerves in order to reach the brain stem.
• Gross Touch sense 
• Just like fine touch sense, their neuron axons carry the information from these receptors in order to reach the brain stem. They usually travel from the other side of the spinal cord to the brain stem then sends information to the deeper part of the cerebrum.

08/11/15

Overview of the Cerebral Cortext:

 If you examine the brain, the first thing you will see is a very wrinkly organ which is the cerebral cortex. The reason that it is wrinkled is that it allows neurons to move smoothly around it's surface area and gives neurons more rooms to send information from 

the brain and to the brain. The brain actual has 4 different areas.

• The Frontal lobe: Is responsible for many things in the brain like thinking or movement. The frontal lobe consists of many areas that help it function.
• Motor Cortex: 
• The motor cortex is responsible for the movement of the body. Fun fact is that you can control someones body if you simulate or tap into the cortex.
• Pre-frontal Cortex: 
• Thinking, imagination, problem solving and other executive things you can do occurs in the pre-frontal cortex. It also supervise different parts of our brain.

• Broca's area:
• Language processing and speech development all occur in Broca's area. Without it, you will be unable to talk.

• The Parietal lobe: Touch and spatial manipulation occurs in the parietal lobe.
• Somato-sensory cortex:
• Touch like pain, pressure and temperature are the information carried by the neurons of the somato-sensory cortex. Example is that if the motor cortex allow us to grab a cup of hot coffee, by the time you touch the cup, the somato-sensory cortex will tell the temperature of the cup. Fun fact is that somato-sensory cortex is right next to the motor cortex allowing easy access to each other.
• Spatial sensory cortex:
• Helps us understand our understand our environment. The spacial sensory cortex automatically allows to plan the movement, to apply the plan of movement and tells where the objective of movement is located. Sense of direction is also involved in the Spatial sensory cortex.
• The Temporal lobe: Responsible for auditory perception. We hear with our ears, we process them in our brain(parietal lobe).
• Wernicke's area:
• Language comprehension and reception all occur in Wernicke's area. Without it, you will be unable to understand language even your own. 
• The Occipital lobe: Vision, everything you see involves with the occipital lobe. We maybe able to see with our eyes but the things we see should be processed through neural images of the occipital lobe.
• Striate cortex:
• This cortex is the main receiving area for visual signals from the eyes and processes the information that it saw.

08.25.15

The Old Brain

If you perform a Sagital slice right across the brain and cut in half, you would see that the brain contains many sections and do you know that there are still old sections in the brain. Very old sections like breathing, blood circulation and sleeping. These sections of the brain had undergone several evolutionary development. These sections are very old that it started functioning the moment we existed. Why didn't the breathing sections get replaced by the evolutionary development? Because as the brain evolves, it only "builds" it's new sections with the old ones. As the brain evolves, it's neurons gets more complex making us do better things but as the brains and neurons get more complicated through evolution allowing them to perform more tasks the old parts of the brain are still there. That's why you can still breath after million years of evolution! So when the brain evolves, it only builds new sections with the old sections. As you go deeper, the areas of the brain gets older and older. The brain stem is also one of the oldest part of the brain because they control breathing, heartbeat and other things that we automatically do like sleeping. The reticular formation is also an old part of the brain that filters information they receive like taking only the important details and ignore the minor ones. They can also distribute information to different parts of the brain for comprehension.

09.22.15

The Cerebellum is located mostly at the bottom of the cerebrum and behind the brain stem. The cerebellum coordinates movement, they make your movement more accurate. Your accuracy depend on your cerebellum. There are three parts of the cerebellum:

• Motor Plan: Tells about muscle duration, contraction, movement and awareness.
• Position Sense: Sends information to the cerebellum and tells them about muscle stretch and the motor plan movement status.
• Feedback: An area of the cerebellum that tells the status of the position sense and motor plan. It acts as an auto-correction in the brain. In case of any movement errors, the Feedback changes muscle and skeletal changes. 

The cerebellum coordinates middle body movements like walking and limb movement. The mouth also functions with the cerebellum, an example is opening your mouth or pronouncing words or just talking familiar words involve lots of work for the cerebellum. Just like the mouth, eye movement also functions with the cerebellum.

10/06/15

Brain-stem
 Basically, the brain-stem is an automatic functioning part of a brain that connects all parts of the nervous system. It connects the cerebrum, cerebellum and the spinal cord. It also connects the cranial nerves which are twelve pairs of nerves that arise directly from the brain, not from the spinal cord, and pass through separate apertures in the skull. Brain-stem sections form a Reticular formation of grey and white matter which is a set of interconnected nuclei that are located throughout the brain-stem.
It is essential for governing some of the basic functions and is one of the oldest portions of the brain.



 The brain-stem provides the main motor and sensory innervation to the face and neck via the cranial nerves. The brain-stem also plays an important role in the regulation of cardiac and respiratory function. It also regulates the central nervous system, and is pivotal in maintaining consciousness and regulating the sleep cycle. The brain-stem has many basic functions including heart rate, breathing, sleeping, and eating.

10/20/15

Sub-cortical Cerebrum
 The sub-cortical cerebrum is located deep inside the cerebrum. It's made mostly white matter and controls different internal sections of the brain.

Sub-cortical Sections

• Internal Capsule
• Conveys pathways for neurons to travel information.
• Corpus Colosum
• Connects information in the left and right hemispheres in the brain.
• Basal Ganglea
• Helps with some areas of the nervous system:
• Emotion
• Cognition
• Thalamus
• Serves as a pathway for:
• Sensory neurons
• Cognition
• Consciousness
• Information Processing  
• Hypothalamus 
• Located below the thalamus and interacts with the:
• Pituitary gland: The master gland that controls all glands in the brain.
• Endocrine system: Controls the glands and its hormones

10/27/15

Cerebral Cortex
A layer of grey matter outside the cerebrum. The cerebral cortex contains different parts with different apperances and functions:

• Apearance of the Cerebral Cortex
• Gyri
• The ridges around the cerebral cortex. Gyrus is a singular form of Gyri
• Sucli
• The lumps on the brain created by the gyrus
• Fissures
• The bigger lumps on the brain created by the gyrus.
• Lobes of the Cerebral Cortex and their Functions
• Frontal Lobe
• Consciousness
• Basic motor information
• Parietal Lobe
• Somatosensory Information
• Temporal Lobe
• Sensory Information
• Types of Cerebral Functions
• Primary Functions
• Basic motor information
• Basic sensory information
• Basic visual information
• Association Functions
• Consciousness
• Cognition
• Emotion
• Language
• Attention

11/03/15

Neurotransmitters

Neurotransmitters are molecules that communicate with between neurons and target cells.

·         Examples of Neurotransmitters

o   Glutamate

§  A common excitatory neurotransmitter

o   GABA

§  A common inhibitory neurotransmitter in the brain

o   Glycene

§  A common inhibitory neurotransmitter in the Spinal Cord

·         Neurotransmitters have projectors that help release them into the brain to control major brain functions.

o   Reticular Activation System

§  Projects neurotransmitters to release glutamate and activate consciousness

o   Acetylcholine

§  Projects axons to release

·         Baselas Nucleus

·         Septal Nuclei

o   Histamine

§  Projects neurons for the:

·         Hypothalamus

o   Which releases dopaminergic neurons

o   Norepinephrine

§  Sends diffuse projections to the cerebral cortex and release Lucus Cerelus

o   Seratonin

§  Release Raphe nuclei in the brainstem

o   Dopamine

§  Released in the Vental Tegmental Area to send neurotransmitters