Trigeminal Nerves

The Trigeminal Nerves are the largest of the cranial nerves. They are derived from the pons of the brain and provide sensory nerons to the face and motor to the teeth and jaw including muscles of the jaw.














Trigeminal nerves have three sudivisions:

V 1. Opthalmic Region- runs through the superior orbital fissure to the eye from the ventral mid-brain to the pons of the brain.
Opthalmic region targets are:
skin of the anterior scalp
nose and nasal cavity
cornea of the eye
lacrimal glands
The opthalmic region of trigeminal nerves is a sensory neuron that functions in corneal reflexes.

V 2. Maxillary Region- runs from the pons of the brain through the foramen rotundum to the face.
Maxillary region targets are:
lower eyelid
the palate
nasal cavity mucosa
skin of the cheek
upper lip upper teeth
The maxillary region of trigeminal nerves is a sensory neuron and functions in the sensation of pain, touch, and sensitivity to temperature. Hmm... I want some ice cream. Ooohhh, I don't like that feeling of ice cream on my teeth. The maxillary region is at work!!

V 3. Mandibular Region- runs through the foramen ovale.
Mandibular region targets are:
temporal region of the scalp
anterior tongue
lower teeth
skin of the chin
masseter muscle
The mandibular region of trigeminal nerves serves as both motor and sensory neurons and functions in activities such as clenching teeth, chewing, and side to side movement of the mandibula. The mandibular region does not function in taste.

Trigeminal Nerves

TRIGEMINAL NERVES

The Lower Limb

Let's take it from the top. The hip joint, which is a ball and socket joint, is where the head of the femur is. The femur fits into a deep cavity in the hip joint called an acetabulum. The pelvic girdle provides the attatchment for the powerful muscles that move the leg at the hip joint and also maitains posture.
Next we have the knee joint. The knee joint is flat with the articular surfaces modified by the medial and lateral cartilages called menisci. This joint has strong ligaments to help maintain its stability. The knee is also known as the patella.
Can you guess the next one? You may have sprained this one before. I'm referring to the ankle joint. The ankle joint is a hinge joint between the lower tibia and fibula and the talus (ankle). It also has strong ligaments on each side. The bones and joints of the tarsus, metatarsus and toes are for locomotion and bearing wight. They do this with adaptation of shape that form the arches in our feet. Like shocks in a car. They provide us with shock absorbancy and mobility. These arches in our feet our made up of ligaments, long tendons, small muscles and the plantar aponeurosis. Plantar? Oh yes, I knew that sounded familiar. I had a plantar's wart when I was a child. Now I know why they called it a plantar's wart. I thought it had something to do with the peanut guy. Anyway, lets gets moving to ... moving.

http://mywebpages.comcast.net/wnor/llbones.htm




















How do our legs move? You're asking me? Okay we'll look into it. There are muscles in the leg that are arranged into compartments. In the thigh there are muscles in the anterior compartment. These are quadriceps. They extend the knee and are supplied by the femoral nerve. The muscles in the adductor compartment squeeze the thighs together. These muscles are supplied movement by the obturator nerve. The posterior compartment which are the hamstrings, extend the hip and flex the knee. The sciatic nerve is responsible for the supply here. Below the knee all muscles are supplied with movement from branches of the sciatic nerve. These branches are tibial or common fibular branches. The muscles of the leg produce movements. Flexion which is a downward at the ankle and extension or dorsiflexion, an upward movement. They also assist in maintaining the arches of our feet. Another type of movement that is below the ankle joint that allows the soles of our feet to move is inward (inversion) or outward (eversion). This makes it easier for us to walk on uneven ground.

www.netterimages.com
fibural nerve obturator nerve sciatic nerve










How about blood supply and arteries? There's alot of that going on in our legs too. Like when your sitting and the computer all night trying to get your blog assignment done and your legs go numb. I'm guessing its a lack of blood flow. The femoral artery is below the inguinal ligament and branches off to the profunda fmoris artery in the upper thigh to supply the muscles in the thigh. The femoral artery continues down the leg through the susartorial canal and becomes the popliteal artery behingd the knee. The popliteal artery then divides into the anterior tibial artery and the posterior tibial artery. Blood flows towards the heart by the action of the skeletal muscles in the lower limb. This venous blood is controlled by valves that ensure flow from the superficial to deep veins. There are two superficial veins. The great saphenous vein which starts anterior and joins the femoral vein at the groin, and the small saphenous vein that joins the popliteal vein in the popliteal fossa.
www.gla.ac.uk

Bones of the Lower Limb
Bones are made of osteocytes which allow for bone growth. Osteocytes are moist, living cells. Bone is also made up of living connective tissue and collagen fibers that are supported by a matrix of calcium salts embedded in compact and spongy bones.
Bone tissue, cartilage and fibrous connective tissue form the ligaments that connect bone to bone. These bones provide protection and support by the muscles attatched being able to move the bones. These bones provide storage of inorganic salts like calcium. A normal blood calcium level is needed for blood clotting and proper functioning of the muscles and nerves.
Each bone is surrounded by a tough membrane called the periosteum, a fibrous connective tissue membrane that merges with tendons and ligaments attatched to the bone. The periosteum contains a network of blood vessels, which supply oxygen, nerves, and nutrients to the bone.
Beneath the peristeum is a thick layer of compact bone found in the diaphysis (shaft of the bone). Compact bone contains yellow bone marrow. Compact bone is composed of cylinders of protein fibers and mineral crystals called lamelle. In the center of each cylinder are the Haversian canals which contain blood vessels and nerves.
Spongy bone which contains red bone marrow is the inside layer of compact bone. Spongy bone is organized near the epiphysis (end of bone). The structure of spongy bone is strong but light in weight. There are both long and short bones in the lower limb.

Joints of the Lower Limb
The types of joints in the lower limb are amphiathrosis which is a slightly moveable joint. This is the joint between the tibia and fibula. Diarthrosis joints are freely moveable joints. Diarthrosis joints are surrounded by a fibrous joint capsule that allows for movement but helps hold bones together and in place. The joint capsule has two layers:
ligaments which are strips of tough connective tissues attatched to the membranes that surround bone and in place.
outer layer of joint capsule produces synovial fluid, which lubricates the surface of a joint by producing a lubricating film. This protects the ends of the bones from friction allowing smooth movement. Small pockets of synovial fluid are formed in diarthrosis joints and are called bursae.
www.netterimages.com
lower motor motor neuron





One more component :
The motor neuron is responsible for sending a message to the muscle causing them to contract.

Images from www.ama-assn.org/ama/pub/category/7173.html

from left to right:

C1 and C2 vertebrae

cervical vertebrae

circiutry for movement

PNS and Vertebral Column

Images from www.unm.edu/~jimmy/spinal_notes.htm


Images from left to right:
Nerve routing
PNS diagram
Nerve groups
Myelin Sheath

PNS

Peripheral Nerve Structure
www.ama-assn.org/ama/pub/category/7173.html

PNS

This is a diagram of the entire PNS obtained from www.ama=assn.org/ama/pub/ctegory/7173.html

Peripheral Nervous System/ Structure of Vertebral Column

The Peripheral Nervous System (PNS) is the nervous system outside of the Central Nervous System (CNS) and consists of bundles of axons (nerve fibers) which are known as fascicles. The axons extend from the brain and spinal cord. These fascicles are surrounded by perineurium. A peripheral nerve is arranged similar to a muscle in terms of connective tissue. It has an outer covering which forms a sheath around the nerve called the epineurium. Between individual nerve fibers is an inner layer of endoneurium. The myelin sheath in peripheral nerves is made up of Schwann cells wrapped in multiple layers around the axons. This applys mostly of the voluntary nerve fibers. Impulses travel along these Schwann cells. In the PNS, spinal nerves are responsible for sending messages by electric impulses to and from the spinal cord. Cranial nerves do the same from the brain. The PNS in our body is responsible for all communication lines that link to the CNS.
The PNS has 2 subdvisions:
Sensory or afferent, which take in information and motor or efferent, which carry out commands. Two kinds of sensory information can be retrieved. They are touch or feeling. Then there is propreoception, which is positional information. For example a person could be blind but know that their hand is out in front of them or by their side. Motor or efferent consists of the somatic nervous system, responsible for it's axons to conduct impulses from the CNS to skeletal muscles. This is voluntary movement in the voluntary nervous system. We are conciously controlling them. The autonomic nervous system (ANS) is almost like it sounds "automatic". The ANS is refered to as the involuntary nervous system. Reactions that are uncontrolled that our body takes care of for us. These are such things as pumping the heart, or activity in the glands and smooth muscles. ANS has 2 functional subdivisions:
Sympathetic- allows the body to mobilize or react in emergency situations. (the more high-strung of the two)
parasympathetic- more of a conservative type, saving energy. Promotes evryday, non-emergency functions.

The vertebral column (spine) is formed from 26 irregular bones that connect to allow for flexability. This is why the spine is curved. There are 5 major divisions of the vertebral column:
7 cervical vertebrae- the vertebral bodies are small compared to the heavier work that the lower spine does, however they have an extensive range of movement.
12 thoracic vertebrae- rib bearing. In order to simplify breathing by the chest expanding, the thoracic vertebrae remains stiff even if the mody is moving.
5 lumbar vertebrae- this is where the main weight of the body is carried. Lumbar vertebrae has a lumbar disk with 2 major components. The outer ring is called the annulus fibrosus made up of strong layers of ligaments. This part helps hold the vertebrae together, limits movement, and contains the inner core and elasticity of the disk. The inner part is called the nucleus pulposus, also known as the shock absorber between vertebrae.
5 sacrum vertebrae- this is important because this is where the sciatic and femoral nerves are located.
4 coccyx- tiny and fused at the terminus of the vertebrae.(tail bone)

Images of Tissue Types

connect. proper
stratified squamous
connective stratified
cuboidal
cartilage



connective tissue

Images of Tissues

Tissue Images

Images in order of appearance:
simple epithelium (www.agen.efl.edu)
simple sqamous (www.lima.ohio-state.edu)
simple cuboidal (www.technion.ac.il)
simple columnar (www.science.tjc.edu)
stratified columnar (www.city.ac.uk)
stratified squamous (www.cytochemistry.net)
stratified cuboidal (www.mhhe.com)
connective tissue (www.rwc.uc.edu)
connective proper (www.mhhe.com)
connective cartilage (www.trc.ucdavis.edu)
connective blood (www.anatomy.iupui.edu)
muscle tissue (www.mhhe.com)
skeletal muscle (www.uoguelph.ca)
cardiac muscle (www.miramar.sdccd.cc.ca.us)
smooth muscle (www.cytochemistry.net)
nervous tissue (www.mhhe.com)
nervous tissue (www.trc.ucdavis.edu)

Tissues

4 Types of Tissues in the Human Body

1. Epithelium
2. Connective
3. Muscle
4. Nervous

Epithelium are sheets of cells. Epithelium acts as a lining both internally and externally in the human body. The functions of epithelium are responsble for protection, filtration, absorption, excretion, and sensory reception. There are 2 classes of epithelium. Each class has 3 types.
Classes:
Simple epithelia- consists of one layer of cells.
Stratified epithelia- consists of multiple layers of cells.
Types:
Squamous- flat and scaly
Cuboidal- cube-like
Columnar- cylinder shaped, look like columns
Simple epithelium are mostly responsible for absorption, secretion, and filtration.
Stratified epithelium comes from the basal layer to replace older cells. Its major function is protection.

Connective Tissues are more plentiful than all other tissues in the human body. Connective tissues are responsible for transportation of subtances in the blood stream, binding and support of body parts, and as an insulation in the human body. There are 4 main classes of connective tissue.

Classes:

Connective tissue proper, including fat and the tissue found in ligaments

Cartilage

Bone

Blood

Connective tissues have 3 types of fibers that provide support:

Collagen Fibers- strongest and most abundant. Formed from collagen

Elastic Fibers- provide stretch and elasticity when necessary

Reticular Fibers- supports soft tissue of the organs

Muscle Tissue is responsible for movement in the human body. There are 3 types of muscal tissue:

Skeletal muscle tissue- provides voluntary movement (you control)

Cardiac muscle tissue- as this muscle tissue moves, it flows blood into circulation. This is involuntary movement (automatically with out you thinking)

Smooth muscle tissue- provides movement of substances internally through the body. This is also an involuntary movement.

Nervous Tissue is the main part of the nervous system. In nervous tissue neurons are transmitted in the brain, spinal cord, and nerves; thus responsible for major functions of the human body. Nervous tissue has 2 main cell types:

Neurons- nerve cells that conduct nerve impulses

Supportive cells- these are non-conducting cells that balance the nervous system

Heidi's Anatomy Blog

Heidi's Anatomy Blog

Organization of The Human Body

There are many levels of structural organization in the human body.

Chemical Level- the simplest level of organization. At this basic level, atoms combine with eachother to form molecules. (waters, proteins) Molecules then form organelles. Organelles are the basic components of cells. These are microscopic.

Cellular Level- we start as a single cell. This cell is the fertilized egg. In this early stage of developement, the cells of the human body are formed. As these cells develope, they release chemicals that develope other cells. These cells all have common functions, but also vary to perform different functions in the body.

Tissue Level- Tissues are the groups of cells that have common functions. There are four basic tissue types:
epithelium- covers the body's surface and acts as a lining
muscle- provides movement in the body
connective tissue- supports and protects the body's organs
nervous tissue- provides communication in the body through electrical impulses transmitted rapidly

Organ Level- an organ, which is formed of at least two tissue types, performs specific functions. These functions are extremely complex.

Organ System- this is when organs work together to accomplish a common purpose at the organ level. Organ systems in the human body are:
cardiovascular system
integumentary system
skeletal system
endocrine system
respiratory system
digestive system
lymphatic system
urinary system
reproductive system

Organismal Level- the highest level of organization. This is where all structural levels work together to form the necessary functions for life.

6 week old embryo 

20 week old embryo 

Here he is! 

8 week old embryo 

Here he is! (38-40 weeks) 

32 week old embryo. Almost ready! 

18 week old embryo 

7 week old embryo