Anatomy Flashcards
What does lymph contain?
Lymph is typically a clear fluid that contains proteins, foreign particles, and a few lymphocytes
What are lymph nodes?
Lymph nodes are encapsulated aggregates of lymphocytes that receive lymph from tissues, trap antigens, and help lymphocytes function in an immune response to an infection.
What is the structure of lymph nodes?
Numerous lymphatic vessels enter the lymph node all around the exterior (these are called afferent lymphatics). A small indentation called the hilum marks the place where a single efferent lymphatic vessel exits and where blood vessels enter and exit
What is the role of the lymph node?
The role of lymph nodes is to filter fluid within the tissue and fight off infection.
How many lymph nodes are there in the body?
There are about 500-700 lymph nodes spread throughout the body, found as clusters surrounding blood vessels
What is lymph?
Lymph is essentially “extra fluid” that is not taken up by capillary beds spread throughout the body.
How much extra fluid does the lymph carry away each day?
Although it sounds like a tiny amount of fluid, the volume of lymph carried away from tissues actually amounts to about 2-4 L every day.
How does the lymph collect fluid?
Starling forces govern the movement of fluid in capillary beds and are a delicate balance of hydrostatic (pressure-based) and oncotic (osmolality-based) forces. They cause a net movement of fluid from capillaries to the surrounding interstitial tissue, and overall this means that more blood volume is brought to the capillary bed by arterioles than is brought back by venules.
Where does the lymph collect the excess interstitial fluid?
Lymphatic vessels weaving between the capillaries, capturing the excess interstitial fluid that is left behind.
What is Lymphedema?
Lymphedema is characterized by the swelling of one or more limbs and sometimes the trunk or genitalia. It can be caused by genetic mutations, secondary infections, or the removal of lymph nodes to treat cancer.
How is lymph carried through the body?
Lymph is carried through the body in two different types of lymphatic vessels: initial lymphatics and collecting lymphatics.
Do skeletal muscles help move lymph?
Yes. The flow of lymph in these larger vessels is also helped by the contraction of skeletal muscle
Do collecting lymphatics have valves?
Yes, to prevent backflow.
Characteristics of lymph movement.
Lymphatic vessels have valves that prevent backflow, and some have a layer of smooth muscle that helps move lymph by peristalsis. Skeletal muscle contraction helps move lymph as well.
Where are the lymph nodes clustered?
Lymph Node Cluster Area of Body Drained
Cervical Head and neck
Hilar Lungs
Mediastinal Trachea and esophagus
Axillary Upper limb, breast, skin above umbilicus
Celiac Liver, stomach, spleen, pancreas, upper duodenum
Superior mesenteric Lower duodenum, jejunum, ileum, colon to splenic flexure
Inferior mesenteric Colon from splenic flexure to upper rectum
Internal iliac Lower rectum to anal canal (above pectinate line), bladder, vagina (middle third), cervix, prostate
Para-aortic Testes, ovaries, kidneys, uterus
Superficial inguinal Anal canal (below pectinate line), skin below umbilicus (except popliteal area), scrotum, vulva
Popliteal Dorsolateral foot, posterior calf
All lymph leads back to two main ducts called the ?
The right lymphatic duct and the thoracic duct
Does the right lymphatic duct or the throacic duct handle more fluid?
The Thoracic Duct - handles all but the upper right quadrant of the body.
Where does the right lymphatic connect, and drain into?
The right subclavian vein.
Are lymph nodes big or small?
Lymph nodes are small, lymphocyte-packed structures that filter lymph and help fight infectious agents and kill malignant cells. They are arranged in clusters throughout the body.
What systems is lymph a part of?
The immune and circulatory systems.
What are the primary lymph organs?
red bone marrow and the thymus gland.
Primary lymphatic organs are where lymphocytes are formed and mature. They provide an environment for stem cells to divide and mature into B- and T- cells:
What are the secondary lymph organs?
The secondary lymphoid organs are the spleen and the lymph nodes. They act as sites for maintaining the mature naive lymphocytes and are also the site where lymphocyte binding to antigen and hence their activation occurs.
What are lymphatic capillaries made of?
Lymphatic capillaries are primarily made out of an endothelium layer that sits on a permeable basement membrane. The flap-like minivalves, located at gap-like junctions in the endothelium, are formed from the overlap of endothelial cells and are normally closed. They allow large particles to enter
What happens when antigens bind to antibodies?
Antibodies are produced by specialized white blood cells called B lymphocytes (or B cells). When an antigen binds to the B-cell surface, it stimulates the B cell to divide and mature into a group of identical cells called a clone. … Antibodies attack antigens by binding to them.
Where is the inguinal region?
The groin.
Where is the axilla?
The armpit is the underside of the shoulder joint, and is among the warmest areas of the body. The armpit is also called the axilla. Blood and lymph vessels serving the arm travel through the armpit.
If a patient has testicular cancer, what lymph nodes will be enlarged?
The para-aortic nodes drain the kidneys as well as the ovaries and uterus in women
Lymph is usually clear, but when is it milky white?
Lymph draining the small intestine contains fat and protein-rich macromolecules called chylomicrons, which imbue the lymph with a white, milky appearance.
What coronary artery is dominant in the vast majority of people?
Dominance is described according to the coronary artery that gives rise to the posterior descending artery. The right coronary artery is dominant in about 85% of the population. A smaller percentage of people have a dominant left coronary artery or have a co-dominant circulation.
What Is the Venous Drainage of the Heart?
There are four main veins draining the blood flow from the heart, all of which drain into the coronary sinus. They are the great, middle, small, and posterior cardiac veins. They coalesce at the back of the heart, forming the coronary sinus within the coronary sulcus. The coronary sinus empties directly into the right atrium
What are the main lymph nodes draining the heart?
The lymphatic channels of the heart drain into the tracheobronchial and brachiocephalic nodes.
How are blood vessels structured?
Blood vessels are composed of three main layers (or tunics): the tunica intima, the tunica media, and the tunica adventitia
Why is the tunica intima smooth?
The nonadherent surface allows red blood cells and platelets to pass by the inner lining of the blood vessels without sticking.
What are the components of the tunica intima structure?
The tunica intima is made up of an endothelial layer, a subendothelial layer, and a basement membrane.
What is the purpose of the vaso vasorum?
Vasa vasorum are the blood supply to the tunica adventitia and outermost parts of the tunica media in larger muscular arteries with thick tunica media.
How do arteries and veins differ in appearance?
Broadly speaking, there are two main types of vessels: arteries and veins. In general, arteries tend to be much more uniformly round than the irregularly shaped veins
What are the key differences between arteries and veins?
Arterial pressure is significantly higher than venous pressure.
Arteries have a very thick tunica media. So the arterial wall is much thicker than the venous wall.
Why are arterial walls much thicker the venous walls?
Arteries must contend with higher overall pressures, as well as significant pressure changes between systole (pump - contract) and diastole (relax).
What are elastic arteries?
Elastic arteries are the largest type of artery. Examples include the aorta, the pulmonary arteries, and the larger branches of the aorta (ie, brachiocephalic, subclavian, carotid, iliac). elastic arteries have a high density of elastin in the tunica media (elastin stained black). These arteries experience high pressure differences between systole and diastole. They expand quickly during systole and then contract back down during diastole.
What are muscular arteries?
Muscular arteries step down a size from elastic arteries. Examples include smaller branches off the aorta (ie, the coronary and renal arteries). The defining feature of the muscular arteries is the paucity of elastin in the tunica media. The muscular arteries have thick walls to contain the overall high pressures but don’t require a lot of elastin since they don’t deal with large pressure differences. They maintain perfusion to some pretty important organs (like the heart and kidneys). In hypotensive states, these muscular arteries can contract quite a lot to maintain perfusion
What is perfusion?
Perfusion is the passage of fluid through the circulatory system or lymphatic system to an organ or a tissue, usually referring to the delivery of blood to a capillary bed in tissue.
What are the smallest types of arteries?
Arterioles are the smallest type of artery (Figure 7). Histologically, arterioles lack an external elastic lamina, and the internal elastic lamina is often incomplete. The arterioles don’t have to deal with pressure changes at all, and as such, they need the least amount of elastin.
What is the main histological difference between arteries and veins?
Arteries have thick tunic media that veins lack.
What happens when venous valves break down?
Venous valves prevent blood pooling in the lower extremities; when they break down, venous pooling worsens, causing deep vein thromboses (DVTs) and venous stasis dermatitis.
How can you distinguish a vein from a venule?
Veins are characterized by the presence of valves.
What is the function of the lymphatic system/
The lymphatic system is primarily responsible for maintaining peripheral fluid balance and transporting lymph to be sampled by the immune system.
How do the three types of capillaries differ?
The three types of capillaries differ in the continuity of the endothelium and basement membrane. Continuous capillaries have intact endothelial and basement membrane layers, fenestrated have discontinuous endothelial layers but intact basement membranes, and in sinusoidal capillaries both are discontinuous.
What distinguishes a lymphatic collecting vessel from a lymphatic capillary?
The presence of a smooth muscle layer that helps propel the lymph back to the heart.. Lymphatic vessels can be distinguished from veins by a thinner wall and larger lumen
Which of the three types of capillaries are least permeable?
Continuous capillaries are the least permeable of the different types of capillaries and can be found in muscles, connective tissue, the lungs, and the skin. They have continuous endothelium and basement membranes.
What are the characteristics of Fenestrated Capillaries?
The endothelial layer has intracellular pores called fenestrae, arrows), but the basement membrane is still continuous. These breaks in the endothelial cells allow the passage of larger molecules out of or into the capillary lumen.
Where are fenestrated capillaries found?
Classically they are found in the glomeruli of the kidney but also appear in the intestines, endocrine glands, and the pancreas.
What are the characteristics of sinusoid capillaries?
The endothelial layer and the basement membrane are both incomplete. Because both layers are incomplete, there is no selective filtration barrier, and large molecules, especially proteins, can pass through the sinusoids (small holes). These types of capillaries are found in the liver and spleen, organs whose primary roles rely on filtering out larger molecules.
When do coronary arteries get their blood - diastole or systole?
Diastole (Relax phase). All other arteries get their blood during systole (contractions)
From what vessel does the liver receive blood?
The hepatic portal vein that is coming from the digestive system.
What vein exits the liver heading to the heart?
The hepatic vein.
Do arteries have tributaries or branches? Which do veins have?
Arteries have branches, veins have tributaries.
How does the lumen appear differently in arteries and veins?
The lumen tends to flatten out in veins (less pressure).
In what type of vasculature is there the most resistance?
Mostly in small arteries and arterioles - 47% of the blood is found here.
How many places on the body can you take a pulse?
10 - radial and ulna pulses cubital pulse brachial carotid facias femoral dorsalis pedis posterior tibila popliteal
What is atherosclerosis?
Atherosclerosis refers to the buildup of fats, cholesterol and other substances in and on your artery walls (plaque), which can restrict blood flow. The plaque can burst, triggering a blood clot. Although atherosclerosis is often considered a heart problem, it can affect arteries anywhere in your body
List heart and circulatory problems.
atheroma thrombus embolus arterial occlusion fissured plague ischemia and cerebral infarction myocardial infarction renal ischemia intermittent claudication
What are sensory neurons?
Sensory neurons relay information about stimuli such as temperature, pressure, light, pain, and certain chemicals back to the brain. They are (in some cases literally) the eyes and ears of the nervous system, collecting information and keeping the CNS informed so it can formulate reactions.
How many kinds of sensory input are there?
Two: Visceral (from the viscera) and Somatic (skin, muscle, bones, joints)
What are the two pathways of the PNS?
sensory (afferent) and motor (efferent).
What’s the most basic distinction we make when talking about the nervous system?
The Central Nervous System (CNS) and the Peripheral Nervous System (PNS)
What makes up the Central Nervous System vs. the Periferal Nervous System?
The CNS is the brain and spinal chord. the PNS is everything else. (Starfleet Command Center vs. Exploratory Vessels and Research Stations scatted thruout the gallaxy. They send reports back to HQ. The officials at HQ issue orders.
Are motor neurons afferent or efferent?
Efferent. Motor neurons send signals in the opposite direction from sensory ones, transmitting commands from the brain to control the contraction of smooth, skeletal, and cardiac muscles
What is the difference between the Visceral and Somatic branches of the PNS?
The somatic motor division sends voluntary commands to skeletal muscles.
Are there any involuntary movements associated with the somatic motor division?
Yes. Reflexes.
Where does “integration” occur in the nervous system?
In the brainstem or posterior horn of the spinal cord, synaptic contact between sensory and motor neurons (integration) occurs. This can happen either directly, as in the case of monosynaptic reflexes, or via interneurons
What does ANS stand for in the nervous system?
autonomic nervous system (ANS). (Remember - this comes from the visceral and hence - all the workings of the ANS are Involuntary.
Which of the somatic or autonomic system involve voluntary movment?
The somatic, plus the exception of reflexes.
What nervous system regulates our survival?
The ANS. The medulla oblongata, part of the brain stem, is the CNS control center for visceral reflexes such as heart muscle contraction, vasomotor control, and respiratory rate and depth
What are the two branches of the ANS?
Sympathetic (fight or flight) and Parasympatheti (Rest and digest).
What do the sympathetic and parasympathetic nervous system regulate in our bodies?
Important body functions like breathing, heart rate, and digestion. If the sympathetic is involved - breathing and heart rate go, digestion goes down.
What are ganglia of the sympathetic nervous system, and where do they live?
Sympathetic nervous system pathways have a preganglionic (axons tend to be shorter) before the ganglion, and postganglionic (after the ganglion) neuron
How does the adrenaline rush work in the sympathetic nervous system?
Some sympathetic neurons start at the spinal cord and go directly out to the adrenal glands, allowing for the immediate release of the hormones epinephrine and norepinephrine. The messages are not first sent to HQ (CNS).
In the sympathetic nervous system, why are preganglion neurons generally shorter than postganglion?
The preganglionic neurons tend to have shorter axons than the postganglionic ones because the ganglia of the sympathetic nervous system are nestled close to the spine. This allows for quick signaling of many different parts of the body when the stress alarm has been sounded.
Does the sympathetic nervous system sometimes inhibit body functions?
Yes. Since the sympathetic nervous system’s job is to get the body into emergency mode, it inhibits functions it considers less important, like digestion.
What does the parasympathetic nervous system do?
It sends signals that slow the heartbeat and respiration rate and allow for digestion to take place.
Which system has longer axons? The sympathetic or parasympatheitc?
The parasympathetic -It not in such a hurry. It also communicates more directly - it doesn’t need to get the whole body riled up
in the parasympathetic nervous system, pre or post ganglionic nerves tend to be larger?
Preganglionic neurons tend to have larger axons than postganglionic ones.
What is the Enteric Nervous System?
It interfaces with the ANS, and regulates secretion, blood flow, and motility within the digestive tract.
Do afferent neurons in the Enteric (gut) nervous system go only to the gut?
No. In addition, afferent neurons send information from the ENS back to the CNS to keep “central command” informed of matters such as tension in the gut wall or the acidity of the stomach.
Where are the sensory nerve somas located?
The somas of sensory neurons are located in dorsal root ganglia. The somas of motor neurons are found in the ventral portion of the gray matter of the spinal cord.
How many type of glial cells are there?
6 - 4 in the CNS (astrocyte, Microglial, Ependymal, Olgodendrocytes) and 2 in the PNS (Satellite and Schwann Cells)
What glials make myelin?
Olgodendrocytes CNS, Schwann Cells PNS
What glial makes spinal fluid?
The Ependymal lines cavities in brain and spinal chord, and creates spinal fluid
What is the roll of Microglial of the CNS?
Defend and protect the immune system, acts as phagocyte
What is the most common glial cell types in the CNS?
Astrocytes - support, regulate ions - most abundant and versatile - star shaped, anchor neurons to blood supply, and govern exchange of materials between neurons and capillaries. Appear black when stained silver.
What do satellite glial cells do in the PNS?
Satellite Cells surround neuron cell bodies
What do Schwann glial cells do?
Insulate and help form myelin sheath
What does the myelin sheath cover?
Axons.
Interesting facts about neurons.
Longest living cells; can’t divide once become nerve cells - no mitosis (IS THIS TRUE ANYMORE?) ; 25% of food you eat each day goes to your brain.
Neuron cell structure?
Dendrites, soma (main body); Axons (sends the message onward).
Shapes of neurons?
multipolar (very common - 99%)
bipolar (rare - retina, etc)
unipolar (some sensory receptors)
pyramidal ?
What are the three types of neuron communication?
afferant (head toward CNS with complaint, info)
efferent (head toward PNS with command)
interneurons, “associated” (in brain - communicates between neurons)
What is phagoytoses in Schwann nerve cells?
If damage occurs to a nerve, it can digest the axon.
Brain structures - also some in spinal cord
cranium meningis cerebral spinal fluid (CSF) dura arachnoid pia
What’s the function of the dura?
The dura mater has several functions and layers. The dura mater is a membrane that envelops the arachnoid mater. It surrounds and supports the dural sinuses (also called dural venous sinuses, cerebral sinuses, or cranial sinuses) and carries blood from the brain toward the heart.
What’s the function of the pia mater?
Together with the other meningeal layers, the function of the pia mater is to protect the central nervous system by containing the cerebrospinal fluid, which cushions the brain and spine. The cranial pia mater covers the surface of the brain.
What roll does the arachnoid play in the brain?
Connected to the dura mater on the side closest to the CNS, this middle layer includes a network of fibers and collagen that are part of the suspension system that helps protect the brain and spinal cord from sudden impact.
What are the meningis?
The primary function of the meninges and of the cerebrospinal fluid is to protect the central nervous system. The pia mater is the meningeal envelope that firmly adheres to the surface of the brain and spinal cord.
What is the neural tube?
The neural tube is the embryonic structure that ultimately forms the brain and spinal cord. The neural tube is formed during a process called neurulation, which begins when the underlying dorsal mesoderm signals the ectodermal cells above it to elongate into columnar neural plate cells.
What are the parts of the primitive brain?
The archipallium or primitive (“reptilian”) brain, comprising the structures of the brain stem – medulla, pons, cerebellum, mesencephalon, the oldest basal nuclei – the globus pallidus and the olfactory bulbs.
What part of the brain is responsible for complex thinking?
The Frontal Lobe—Located under the forehead, the frontal lobe controls reasoning, planning, voluntary movement, and some aspects of speech. The prefrontal cortex is the part of the frontal lobe right behind the forehead.
In embrylogy, what develops from the neural tube and when does it begin?
5 weeks. The brain develops into three types (pro, mes, and thombacephalon), and then 5 (vesicles, tel, di, meta and myancephalon) , and finally the adult brain has four parts: cerebral hemisphere, diencephalon (interbrain), brain stem, cerebellum
What is the reflex arc?
A reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neurons do not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the brain. Sometimes message is generated and responded to on same side of body; sometimes not.
What is the muscle stretch reflex?
The stretch reflex (myotatic reflex) is a muscle contraction in response to stretching within the muscle. A spinal reflex is a fast response that involves an afferent signal into the spinal cord and an efferent signal out to the muscle.
What is Somatosensation?
Somatosensation is a collective term for the sensations of touch, temperature, body position, and pain recognized through neural receptors in the skin and certain internal organs. Thus, it includes processes such as” mechanoreception. thermoreception. proprioception.
How many spinal nerves are there?
31 pairs. Cervical 8, Throacic 12, Lumbar 5, Sacral 5, Coccyx 1
How many cranial nerves are there?
12 pairs.
What is a dorsal root ganglion?
A dorsal root ganglion (or spinal ganglion; also known as a posterior root ganglion) is a cluster of neurons (a ganglion) in a dorsal root of a spinal nerve. The cell bodies of sensory neurons known as first-order neurons are located in the dorsal root ganglia.
What does dorsal root gangla do?
The dorsal root ganglia contain cell bodies for sensory nerves that carry sensory information to the spinal cord.
What are the denticulate ligaments?
The denticulate ligaments are bilateral triangular lateral extensions of pia mater that anchor the spinal cord to the dura mater. They are formed by pia mater of the spinal cord coursing in-between the dorsal and ventral nerve roots bilaterally.
Function of Grey matter?
Grey matter contains most of the brain’s neuronal cell bodies. The grey matter includes regions of the brain involved in muscle control, and sensory perception such as seeing and hearing, memory, emotions, speech, decision making, and self-control.
Function of white matter?
Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distribution of action potentials, acting as a relay and coordinating communication between different brain regions. White matter is named for its relatively light appearance resulting from the lipid content of myelin.
What is the function of the lateral grey horns?
The lateral column is only present in the thoracic region and upper lumbar segments.
The lateral grey column, or the lateral horn of spinal cord, is part of the sympathetic nervous system and receives input from brain stem, organs, and hypothalamus.
What is the function of the anterior horn?
One of the divisions of the grey matter of the spinal cord, the anterior horn contains cell bodies of alpha motor neurons, which innervate skeletal muscle to cause movement
Functions of the ventral horn?
The ventral horns contains the cell bodies of motor neurons that send axons via the ventral roots of the spinal nerves to terminate on striated muscles. … The ventral (and ventrolateral or anterolateral) columns carry both ascending information about pain and temperature, and descending motor information.
What is a cutaneous nerve?
A nerve that provides nerve supply to the skin.
What would happen if the anterior Ramus of a spinal nerve was damaged?
It will not affect other body functions such as sensation which is controlled by the dorsal roots of the spinal nerves. The ventral root generally controls the muscles and movements. If it is damaged, there will be weakness or paralysis in the muscles in the particular area of the body.
What are the effector organs?
Effector organs of the Autonomic pathway are: cardiac muscle, smooth muscle, glands, adipose tissue, kidney and other organs. … Cell body in the CNS, preganglionic neuron in the PNS, autonomic ganglion, postganglionic neuron to the effector organs.
What are the effector organs?
Effector organ a muscle or gland that contracts or secretes, respectively, in direct response to nerve impulses.
Cranial nerve mneumonic from C1 - C12?
Ooh, ooh, ooh to touch and feel very good velvet. Such heaven. O: olfactory nerve (CN I) O: optic nerve (CN II) O: oculomotor nerve (CN III) T: trochlear nerve (CN IV) T: trigeminal nerve(CN V) A: abducens nerve (CN VI) F: facial nerve (CN VII) A: auditory (or vestibulocochlear) nerve (CN VIII) G: glossopharyngeal nerve (CN IX) V: vagus nerve (CN X) S: spinal accessory nerve (CN XI) H: hypoglossal nerve (CN XII)
Cranial nerve mnemonic for function?
Some say marry money but my brother says big brains matter more
S: sensory (olfactory nerve - CN I) S: sensory (optic nerve - CN II) M: motor (oculomotor nerve - CN III) M: motor (trochlear nerve - CN IV) B: both (trigeminal nerve - CN V) M: motor (abducens nerve - CN VI) B: both (facial nerve - CN VII) S: sensory (vestibulocochlear nerve - CN VIII) B: both (glossopharyngeal nerve CN IX) B: both (vagus nerve - CN X) M: motor (spinal accessory nerve - CN XI) M: motor (hypoglossal nerve - CN XII)
Where does the spinal chord extend from?
The foramen magnum where it is continuous with the medulla to the level of the first or second lumbar vertebrae
What are the four plexis of the spinal chord?
Cervical, brachial, Lumbar, Sacral
What is a nerve plexus?
A nerve plexus is a plexus (branching network) of intersecting nerves. A nerve plexus is composed of afferent and efferent fibers that arise from the merging of the anterior rami of spinal nerves and blood vessels.
What is the spinal chord covered with?
Transparent Pia Mater.
What’s the dural root sleeve?
It actually consists of two nerve roots, a motor and sensory, inside a sleeve of dura. At a point just beyond the ganglion the two roots blend together and become a typical mixed peripheral nerve. At this same point the dural sleeve becomes adherent to the nerve and henceforth is called the epineurium.
What is the function of white matter in your spinal column?
White matter’s job is to conduct, process, and send nerve signals up and down the spinal cord.
The white matter of your brain and spinal cord is composed of bundles of axons. These axons are coated with myelin, a mixture of proteins and lipids, that helps conduct nerve signals and protect the axons.
What’s the posterior root ganglion?
A posterior root ganglion is a cluster of nerve cell bodies found immediately outside of the spinal column whose axons are normally responsible for transmitting sensory signals to the spinal cord.
What’s the function of the anterior gray horn in the spinal column?
one of the divisions of the grey matter of the spinal cord, the anterior horn contains cell bodies of alpha motor neurons, which innervate skeletal muscle to cause movement.
Where are the meninges located and what is their function?
The meninges are the dura mater, the arachnoid mater, and the pia mater. Cerebrospinal fluid is located in the subarachnoid space between the arachnoid mater and the pia mater. The primary function of the meninges is to protect the central nervous system.
What are the differences between the posterior and anterior grey horn matter?
The posterior horn is responsible for sensory processing. The anterior horn sends out motor signals to the skeletal muscles. … The fibers that cause contraction of skeletal muscles are the axons of these neurons.
What’s the difference between the anterior and posterior rootlets?
Anterior rootlets carry motor information out of the spinal cord (i.e. they contain efferent fibers) while the posterior rootlets carry sensory information into the spinal cord (i.e. they contain afferent fibers).
Are cranial nerves paired?
Yes. All cranial nerves are paired, which means that they occur on both the right and left sides of the body. The muscle, skin, or additional function supplied by a nerve on the same side of the body as the side it originates from, is referred to an ipsilateral function.
What’s a mixed nerve?
A spinal nerve is a mixed nerve, which carries motor, sensory, and autonomic signals between the spinal cord and the body. In the human body there are 31 pairs of spinal nerves, one on each side of the vertebral column.
Are all cranial nerves mixes?
Five cranial nerves have mixed sensory, motor and parasympathetic function. … The mixed cranial nerves are CN III Occulomotor, CN V Trigeminal, CN VII Facial, CN IX Glossopharyngeal and CN X Vagus.
What does each spinal nerve control?
The spinal nerves act as “telephone lines,” carrying messages back and forth between your body and spinal cord to control sensation and movement. Each spinal nerve has two roots (Fig. 8). The ventral (front) root carries motor impulses from the brain and the dorsal (back) root carries sensory impulses to the brain.
What’s a spinal ganglion?
A dorsal root ganglion (or spinal ganglion; also known as a posterior root ganglion) is a cluster of neurons (a ganglion) in a dorsal root of a spinal nerve. The cell bodies of sensory neurons known as first-order neurons are located in the dorsal root ganglia.
What is the function of the posterior ramus?
Because each spinal nerve carries both sensory and motor information, spinal nerves are referred to as “mixed nerves.” Posterior rami carry visceral motor, somatic motor, and sensory information to and from the skin and deep muscles of the back.
What are dorsal and ventral Rami?
The dorsal and ventral rami contain nerves that provide visceral motor, somatic motor, and sensory information, with the dorsal ramus feeding the dorsal trunk (skin and muscles of the back), and the ventral ramus feeding the ventral trunk and limbs through the ventrolateral surface.
Where is the vagus nerve and what does it do?
The vagus nerve runs from the brain through the face and thorax to the abdomen. It is a mixed nerve that contains parasympathetic fibres. The vagus nerve has two sensory ganglia (masses of nerve tissue that transmit sensory impulses): the superior and the inferior ganglia.
Are the Autonomous and Visceral Nervous Systems or Visceral Motor System the same thing?
Yes.
Describe the Autotomic Nervous System Features:
- Autonomic sensory (chemoreceptors, mechano- (stretch) receptors
- Motor neurons regulate visceral activities; can function independently of ANS
- Preganglionic and postganglionic neurons
- Acetylcholine or norepinephrine
Describe the Somatic Nervous System Features:
Somatic senses (pain, thermal, tactile, proprioreceptive)
Somatic motor neurons-skeletal muscle
Usually voluntary
Motor units
Acetylcholine
Which of these two systems, the Autonomic or Somatic, has ganglions?
The Autonomic.
Is the sympathetic system in the thoracolumbar or cranoisacral division?
Thorcolumbar. The parasympathetic is in the craniosacral division.
What are the different types of ganglia?
Sympathetic
Sympathetic trunk (paired)
Innervate organs above the diaphragm
Superior, middle, inferior cervical ganglia
Prevertebral (unpaired)
Below the diaphragm
Celiac, superior and inferior mesenteric ganglia
Parasympathetic
Preganglionic axons are longer than in sympathetic ganglia
Preganglionic neurons are myelinated, postganglionic neurons are not
What are the actions of neurotransmitters in ANS?
Acetylcholine (cholinergic neurons)
All preganglionic
Sympathetic postganglionic innervation of sweat glands
All parasympathetic postganglionic neurons
Nicotinic, muscarinic receptors
Norepinephrine (adrenergic)
α and β receptors
Can be excitatory or inhibitory
Functions of ANS?
“Fight or flight” (sympathetic)
More widespread and longer lasting
Norepinephrine and epinephrine can act as hormones as well as neurotransmitters
“Rest and digest” (parasympathetic)
Salivation, lacrimation, urination, digestion and defecation
Distinction between Control of Autonomic Functions?
Reflexes
Blood pressure
Digestion
Defecation and urination
Control within brain Brain stem (cardiovascular, swallowing , digestion)
Embriologically, what does the nervous system look like?
The central nervous system (CNS) is formed in week 3 of development, during which time the neural plate develops
The neural plate, consisting of neuroectoderm, becomes the neural tube, which gives rise to the brain and spinal cord.
What is neurolation?
Neurulation is the transformation of the ectoderm overlying the notochord into a neural tube, which is flanked by 2 longitudinal formations, the neural crests
The rostral part of the neural tube becomes the adult brain.
The caudal part of the neural tube becomes the adult spinal cord.
Embiologically, where does the PNS come from?
Three sources:
- Neural crest cells
- Neural tube, which gives rise to all preganglionic autonomic nerves (sympathetic and parasympathetic) and all nerves (-motoneurons and -motoneurons) that innervate skeletal muscles
- Mesoderm, which gives rise to the dura mater and to connective tissue investments of peripheral nerve fibers (endoneurium, perineurium, and epineurium)
Embriologically, what’s up with neural crest cells?
The neural crest cells differentiate from cells located along the lateral border of the neural plate, which is mediated by BMP-4 and BMP-7.
Neural crest cells undergo a prolific migration throughout the embryo (both the cranial region and trunk region) and ultimately differentiate into a wide array of adult cells and structures
Neural Crest cells coming from the Dorsal Neural Tube become…?
Neurons and glia of cranial ganglia, cartilage and bones, connective tissue, Sympathetic Adrenal Cells, Sensory neurons and glia, pigment
Cranial Neural Cells become..
Cranial neural crest cells differentiate into the following adult cells and structures:
Pharyngeal arch skeletal and connective tissue components
Bones of neurocranium; Pia and arachnoid
Parafollicular (C) cells of thyroid
Aorticopulmonary septum; Odontoblasts (dentin of teeth)
Sensory ganglia of cranial nerve (CN) V, CN VII, CN IX, and CN X
Ciliary (CN III), pterygopalatine (CN VII), submandibular (CN VII), and otic (CN IX) parasympathetic ganglia.
Are there different locations of neural crest cells?
Neural crest cells originating from different positions along the anterior-posterior axis develop into various tissues. These regions of neural crest can be divided into four main functional domains, which include the cranial neural crest, trunk neural crest, vagal and sacral neural crest, and cardiac neural crest.
Types of ganglia
Sympathetic and Parasympathetic - differences?
-sympathetic - above diaphragm paired; below diaphragm unpaired; preganglia shorter; deliver acetycholine (ganglia) - Norepinephrine to target
Parasympathetic - preganglia longer, post ganglia NOT myelinated - acetycholine x 2 usually.
What is a pseudogangion?
It looks like a ganglion, but only has nerve fibers and has no nerve cell bodies. Found in the teres minor muscle and radial nerve.
What is a plexus?
Ganglia often interconnect with other ganglia to form a complex system of ganglia known as a plexus.
What are the three types of ganglia?
Dorsal root (aka spinal ganglia) for sensory (afferent) neurons; cranial nerve; and Autonomic.
In the autonomic nervous system, what are pre and post ganglionic fibers?
Pre - from CNS to glanglia -
Post - from ganglia to effector organ
What is the basal ganglia?
In the brain - a group of nuclei interconnected with cerebral cortex, thalamus, and brainstem. (motor control cognition, emotions, learning)
Where do sympathetic preganglionic nerves live?
Preganglionic cells of the sympathetic nervous system are located between the first thoracic segment and third lumbar segments of the spinal cord. Postganglionic cells have their cell bodies in the ganglia and send their axons to target organs or glands.
In the sympathetic nerve system, trace the travel route from spinal column to effector organ.
Arive from T1 - L2 regions’ lateral horn of grey, emerge via ventral root, enter their respective spinal nerve, enter white ramus - from there - four routes to synapse, up, down, entry level, or straight through (splanchnic).
Can a pregangionic fibre synapse with more than one posganglionic fibers?
Yes. 15 - 20.
When do neurons in the sympathetic system enter the gray ramu (less mylientated)?
When the fibres leave the sympathetic chain.
What is collateral ganglia?
Also called the preverterbral ganglia, the nervous receive input from the splanchnic nerves and innervate organs of the abdominal and pelvic ring. - including the ciliac ganglia, superior mesenteric ganglia, and inferior mesenteric gnaganglia.
What is a dorsal route ganglia?
Sensory nerve cell bodies - carrying info to spinal cord.
Difference between dorsal and ventral (anterior/motor) root?
The dorsal (posterior) or sensory root bears a dorsal root ganglion (DRG) containing the cell bodies of the sensory neurons. The ventral (anterior) or motor root consists of axons from the lower motor neurons in the ventral horn of the spinal cord.
____ are cells in the PNS which surround the cell bodies of neurons which are grouped in ganglia. They maintain the microenvironment and provide insulation.
Satellite cells.
What are the “nodes of Ranvier’?
Short unmyelinated regions between adjacent Schwann or oligodendrocytes.
In the CNS, _____ are cells which are phagocytic: they defend against pathogens and ingest cellular debris.
Microglia.
The RER and Golgi bodies in neurons, taken together, are called _____.
Nissi bodies. It’s function is to produce neurotransmitters
Where are Nissi bodies found?
in the soma.
The cell body and dendrites of a neuron contain _____ which allow them to respond to neurotransmitters.
chemically gated ion channels.
One of the main differences between an axon and a dendrite is that the axon contains
_____ ion channels, while the dendrite contains _____ ion channels.
voltage gated; chemically gated
? i wonder if this is true?
There is a secretory region at the distal end of each axon which releases _____.
neurotransmitters
A(n) _____ is a collection of neuronal cell bodies located inside of the CNS. nucleus
nucleus
- A(n) _____ is a group of neuronal cell bodies located in the PNS
ganglion
A(n) _____ is a collection of neuronal axons with a common origin and destination found
in the CNS.
tract
One of the differences between a nerve and a tract is that a(n) _____ does not carry its
own blood and lymphatic supply.
tract
A(n) _____ is a collection of neuronal axons, blood vessels, and connective tissues in the
PNS
nerve
In the PNS, a Schwann cell encloses the axon of a single neuron with an empty portion of
its _____.
plasma membrane
The _____ is the nucleus and cytoplasm of a Schwann cell which is wrapped around an
axon.
Neurilemme
A single Schwann cell is capable of interacting with the axons of how many neurons?
one vs. oligodendocytes in the CNS that can interact with many.
Neurons can be classified functionally as _____, _____ or _____.
sensory, motor, interneurons - OR, afferent, efferent, and association neurons
Action potentials in neurons are generated in the region called the _____.
trigger zone
Resting membrane potential in many nerve cells is roughly _____ millivolts.
-70
The major ions which contribute to the resting membrane potential are _____ and _____.
sodium (more on the outside), potassium (more on inside).
Only two types of cells can generate action potentials: _____ cells and _____.
muscle and nerve cells (neurons)
The speed of an action potential is greatest when it is traveling through an axon which is
_____.
myelinated
_____ are chemicals used for neuronal communication with the body and the brain.
Neurotransmitters
The _____ is the tube of ectoderm formed early in embryological development as the
embryonic tissue folds longitudinally.
embryonic neural tube
The three primary brain vesicles are formed during the _____ week after conception.
4th
Between the fifth week post-conception and birth, the prosencephalon (aka _____)
develops to produce the _____ and _____ of the adult brain
forebrain, cerebrum, diencephalon
Between the fifth week post-conception and birth, the mesencephalon develops to
produce the _____ of the adult brain.
midbrain
Between the fifth week post-conception and birth, the rhombencephalon (aka _____)
develops to produce the _____, _____ and _____ of the adult brain.
hindbrain, pons, medulla, cerebellum
In an adult, the _____ are a functional unit and are called the brain stem
midbrain, pons, and medulla oblongata
(True/False) The neural tube, initially hollow, remains filled with liquid in the adult.
true
The shape and size of the skull causes the embryonic neural tube to _____ during
development.
flex and fold
_____ form the gray matter of the CNS
Neuron bodies and unmyelinated axons
White matter is composed of _____.
myelinated neuronal axons
Gray matter is found in the cortex of the _____ and _____.
cortex, cerebellum
_____ surrounds the central core of gray matter in the CNS.
White matter
_____ are fluid-filled chambers within the brain.
ventricles
_____ is the fluid which surrounds, and fills the hollow areas in, the CNS.
cerebrospinal fluid
The left hemisphere contains Broca’s area, which is responsible for _____, _____ and
_____.
planning speech, thinking in words; writing
For historical reasons, the basal nuclei are also known as the _____, a name whose use is discouraged.
basal ganglia
The continuation of automatic behaviors necessary for survival (e.g., breathing) is
controlled by the _____.
brainstem
Ten of the twelve pairs of cranial nerves originate in the _____.
brain stem
The _____ are a set of three connective tissue membranes that surround the CNS.
meninges
The tough, fibrous, double-layered, outermost meninx is the _____.
dura mater
The _____ is the middle meninx.
arachnoid
The ____ is the innermost meninx: it clings tightly to the surface of the brain, even in the
sulci.
pia mater
The wide, cerebrospinal fluid containing space is between the _____ mater and the pia
mater and is called the _____ space.
arachnoid, subarachnoid
_____ fills the ventricles and surrounds the brain and spinal cord, acting as a shock
absorber, distributing nutritive materials, removing wastes, and providing a chemically
stable environment.
CSF
Impaired blood circulation to the brain due to a blocked or broken vessel is known as a(n)
_____, _____ or _____.
cerebrovascular accident; stroke;brain attack
(True/False) Most of the neuronal death due to a stroke occurs several minutes or even
hours after the stroke begins, allowing time for emergency treatment to have a major
effect.
true
An abnormal build up of beta-amyloid protein fragments in the regions surrounding
neurons, and of neurofibrillary tangles in the cytoplasm of pyramidal neurons and in that of
neurons whose axons connect with them, are the causes of neuronal death in _____.
Alzheimer’s
In the elderly, drug reactions, poor circulation, or disease, all of which may be curable, can
mimic the dementia caused by _____, which is not.
Alzheimer’s
In Huntington’s Disease, damage to the caudate nucleus, one of the basal nuclei, caused by an abnormal protein leads to _____ and eventually to death.
chorea (involuntary muscle spasms)
Loss of dopamine-producing neurons in the substantia nigra leads to tremor, muscular
rigidity, slow movement and postural instability in _____.
Parkinson’s
The _____ is formed of paired strips of cells arising from the ectoderm at the margin of the neural tube.
neural crest
The spinal cord itself is formed from the _____, and the dorsal root ganglia are formed
from the _____.
neural tube, neural crest
The spinal cord extends from the _____ to the _____; below L1 it branches to form the
_____.
skull, L1 vertebra, cauda equina
In addition to the vertebral column, the spinal cord is protected by the _____ and _____.
meninges, CSF
The butterfly-shaped central core of gray matter in the spinal cord can be divided into
three regions. The _____ contains the cell bodies of somatic motor neurons.
anterior horn
The butterfly-shaped central core of gray matter in the spinal cord can be divided into
three regions. The _____ contains the cell bodies of the autonomic motor neurons and is present only in the thoracic and upper lumbar (L1 and L2) regions.
lateral horn
The butterfly-shaped central core of gray matter in the spinal cord can be divided into
three regions. The _____ contains interneurons.
posterior horn
The axons of the neurons from the _____ and _____ horns emerge together as the
ventral roots.
lateral, anterior
The _____ are formed from the cell bodies of sensory neurons whose axons branch to
extend inward to the spinal cord and outward to the body.
dorsal root ganglia
_____ are white-matter columns consisting of the myelinated axons of neurons associated with the spinal cord.
funiculi
The neuronal cell bodies for the ascending pathways of the spinal cord itself are found in
the _____ or _____.
dorsal horn, dorsal root ganglia
Neurons in the _____ have axons which extend from the receptor to the spinal cord, or in
some cases all the way to the brain.
dorsal root ganglia
Neurons of the dorsal horn receive signals from those in the _____. Their own axons
extend to reach neurons in the brain stem, diencephalon, etc.
dorsal root ganglia
What do merkel cells do?
Let you feel light touch
What do Langerhaus cells effect?
immune system, found in the epidermis. Langerhans cells (LC) are tissue-resident dendritic cells of the skin, and contain organelles called Birbeck granules. They are present in all layers of the epidermis and are most prominent in the stratum spinosum.
Grey matter - where it is?
In the center of the spinal cord and on the outside of the brain - somas
White matter - where it is?
On the edges in the spinal column (surrounding the grey horns) and on the inside of the brain - full of axons traveling together (tracts). Deeper in the brain are the nuclei.
What are dermatomes
Dermatomes are areas of skin that are connected to a single spinal nerve. … Spinal nerves help to relay information from other parts of your body to your central nervous system. As such, each dermatome transmits sensory details from a particular area of skin back to your brain.
Dorsiflexion vs. Plantarflexion
Dorsiflexion is the backward bending and contracting of your hand or foot.
Eversion vs. Inversion of foot.
Eversion is the movement of the sole of the foot away from the median plane
thumb movements?
Faces laterally, moving forward (abduction). If moves laterally - flexion. Touching other digits - Opposition
Where do movement of forearm come from?
Radioulnar jt - pronation, supination.
What is carpal?
wrist
Occipital?
back of head
antebracial?
forearm
tarsal?
ancle
sural?
calf
Boundary between upper and lower limb?
upper gluteal
5 regions of anatomy
head area, thorax, abdomen, , upper limb, lower limb
Muscle movement is caused by?
Contractile cells
Three types of muscles?
Skeletal
Cardiac,
Smooth
Describe skeletal muscles?
voluntary, striated, two attachments - origin - (more fixed and proximal) insertion.
Enclosed by epimyseum, smaller bundles (perimysium, each muscle fiber (endomyseium
Lou Gehrig’s disease?
Fatal neuro disease, attacks neurons responsible for controlling voluntary muscles - brain unable to control voluntary movements
Describe cardiac muscles
- Involuntary, striated, forms the myocardium (middle layer of heart)
- Innervated by autonomic NS
- Includes specialized myocardial fibers that form cardiac conduction system.
Describe smooth muscles?
- Involuntary, nonstriated,
- generally arranged in two layers - circular and longidudinal
- Innervated by Auto NS regulating size of lumen
- Peristaltic waves (rhythmic contractions) in GI tract, uterine tubes, ureters, and other organs
What is a Tendon?
fibrous bands of dense connective tissue that connect muscles to bones or cartilate
What are Ligaments
fibrous bands that connect bones to bones or cartilage or are folds of peritoneum serving to support visceral structures
What is Raphe?
Is the line of union of symmetrical structures by a fi brous or tendinous band such as the
pterygomandibular, pharyngeal, and scrotal raphes.
Retinaculum?
■ Is a fibrous band that holds a structure in place in the region of joints.
Bursae?
■ Are fluid-filled flattened sacs of synovial membrane that facilitate movement by minimizing
friction.
Synovial Tendon Sheaths?
■ Are synovial fl uid-fi lled tubular sacs around muscle tendons that facilitate movement by
reducing friction.
What is Fascia and how many kinds are there?
a fibrous sheet that envelopes the body under skin - may limit spread of pus and extravasated fluids such as urine and blood.
-Superficial, Deep
Superficial Fascia?
Is a loose connective tissue between the dermis and the deep (investing) fascia and
has a fatty superficial layer (fat, cutaneous vessels, nerves, lymphatics, and glands)
and a membranous deep layer.
Deep Fascia?
■ Is a sheet of fibrous tissue that invests the muscles and helps support them by serving
as an elastic sheath or stocking.
■ Provides origins or insertions for muscles, forms fibrous sheaths or retinacula for tendons, and forms potential pathways for infection or extravasation of fluids.
What is Hilton’s Law?
The nerve supplying a joint also supplies the muscles that move the joint and the skin covering the insertion of such muscles
What is a joint?
Union between two or more bones. Classified by structure: fibrous, cartilaginous, synovial
Features of Fibrous Joints
- no joint cavity
- joined by fibrous tissue
- little or no movement
Sutures (betw flat bones of skull)
Syndremoses (inferior tibiofibular and tympanostrapedial syndesmoses
Features of Cartilaginous Joints?
-united by cartiage
-no joint cavity
Primary vs. Secondary Joints
Names 6 types of Synovial Joints
- Plane (gliding) - (proximal tibiofibular, intertarsal…)
- Hinge (elbow, ankle, .. )
- Pivot (radioulnar, ..)
- Condylar (allow flexion/extension - in wrist, knee….)
- Saddle (carpometacarpal in thumb; between femur and patella)
- Ball and Socket (shoulder, hip)
What is Osteoarthritis?
A noninflammatory degenerative joint disease characterized by
degeneration of the articular cartilage and osseous outgrowth at the margins. It
results from wear and tear of the joints; commonly affects the hands, fi ngers, hips, knees, feet, and
spine; and is accompanied by pain and stiffness
What is Rheumatoid arthritis?
An inflammatory disease
primarily of the joints. It is an autoimmune disease in which the immune system attacks the synovial
membranes and articular structures, leading to deformities and disability
What is gout?
Gout is a painful form of arthritis and is caused by too much uric acid in the blood. Uric acid crystals are
deposited in and around the joints,
What is the axial skeleton vs. the appendicular?
The axial skeleton (bones of the head, vertebral column, ribs, and sternum) and the appendicular skeleton (bones of the extremities).
What type of tissue are bones?
Are calcified connective tissue consisting of cells (osteocytes) embedded in a matrix of ground substance and collagen fibers, have a superficial thin layer of compact bone around a central mass of spongy bone, and contain internal soft tissue, the marrow, where blood cells are formed.
Function of bones?
Serve as a reservoir for calcium and phosphorus and act as biomechanical levers on which muscles act to produce the movements permitted by joints
How are bones classified?
Shape: long, short, fl at, irregular, and sesamoid bones and, according to their developmental history, into endochondral and membranous bones.
Long Bones
- include humerus, radius, etc
- develop by replacement of hyaline cartilage plate (endochondral ossificaiton)
- have a shaft (diaphysis), two ends (epiphyses.
What is Diaphysis of long bones?
■ Forms the shaft (central region) and is composed of a thick tube of compact bone that encloses the marrow cavity.
What is Metaphysis of Long Bones?
Growth zone between diaphysis and epiphysis
What is Epiphyses in Long Bones
expanded articular ends, separated from the shaft by the epiphyseal plate during
bone growth and composed of a spongy bone surrounded by a thin layer of compact
bone.
Describe features of Short Bones?
■ Include the carpal and tarsal bones and are approximately cuboid shaped.
■ Are composed of spongy bone and marrow surrounded by a thin outer layer of compact
bone.
Describe features of Flat Bones
- Sternum, ribs, scapulae, vault of skull
- Two layers - Compact bone enclosing spongy bone and marrow space
- Articular surfaces covered with fibrocartilage and grow by replacement of connective tissue
Describe Irregular Bones?
- Include bones of mixed shapes such as bones of the skull, vertebrae, and coxa.
- Contain mostly spongy bone enveloped by a thin outer layer of compact bone.
Sesamoid Bones
■ Develop in certain tendons and reduce friction on the tendon, thus protecting it from
excessive wear.
■ Are commonly found where tendons cross the ends of long bones in the limbs, as in the
wrist and the knee (i.e., patella).
Osteoblast vs. Osteoclas?
Osteoblast synthesizes new bone and osteoclast functions in the resorption (break down bone matrix and release calcium and minerals) and remodeling of bone.
Osteomalacia ?
is a gradual softening of the bone due to failure of the bone to calcify because of lack of vitamin D or renal tubular dysfunction.
Osteopenia?
is a decreased calcification
of bone or a reduced bone mass due to an inadequate osteoid synthesis.
Osteoporosis?
is an age related disorder characterized by decreased bone mass and increased susceptibility to fractures. It occurs when bone resorption outpaces bone formation
Osteopetrosis?
is an abnormally dense bone, obliterating the marrow cavity, due to defective resportion of
immature bone.
Spinal nerves - are formed from what kind of roots?
Are formed from dorsal and ventral roots; each dorsal root has a ganglion that is within
the intervertebral foramen.
How are Spinal Nerves connected?
With the sympathetic chain ganglia by rami communicantes
Dorsal root ganglion?
Spinal nerves - generating somatic afferent and visceral afferent fibers.
-Dorsal root ganglia consist of cell bodies of the unipolar or pseudounipolar neurons and have no synapses
Anterior horn of the spinal cord controls?
Somatic efferent in the grey matter
Lateral horn of the spinal cord controls?
Visceral efferent in the grey matter. It is only present in the thoracic region and upper lumbar segments.
Difference between ventral and dorsal primary rami?
The ventral primary rami enter into the formation of plexuses (i.e., cervical, brachial, and lumbosacral); the dorsal primary rami innervate the skin and deep muscles of the back.
Skin is made of how many layers?
3
- epidermis (stratified epithelium developed from ectoderm, avascular)
- dermis, contains down growths from epidermis, develops from mesoderm– hypodermis (fatty layer)
Appendages of Skin?
- sweat glands + mammary, sebaceous gland, hair - all develop from down growths in epidermis.
- nails -
