Nervous & Endocrine Systems Flashcards
What are the three anatomical regions of neuron?
1) Cell body (soma)
2) Dendrites
3) Axon
What is the soma?
Contains nucleus of neuron.
- processing of information occurs
- memories/experiences are stored
What is the dendrites of neuron?
Dendrites receive input from other neurons and transmit the information to the cell body.
What do axons of neuron do?
Axons transmit input from soma to other cells.
What is an Axon?
The axon is a singe branch off the cell body and will branch multiple to thousands of times at the axon terminal with each branch forming a synaptic knob that will synapse with one other cell.
Myelin sheath
Encases the axon; insulates
What is nodes of Ranvier?
Gaps in the myelin sheath
What is a synaptic knob?
The end of the axon branches extensively. The axon terminal ends in a knob.
-within the knobs are vesicles containing a neurotransmitter
Two types of myelin sheaths
1) Oligodendrocytes in the CNS
2) Schwann cells in PNS
What are the functions of axons?
Convey nerve impulse (action potential) from the cell body to the end of the neuron
-transmits information from the neuron to another neuron to another cell of the body
What is the action potential?
An electrical charge
Neuron Synapse: Chemical
What is a chemical synapse?
Most common type of synapse within the nervous system
What is a Presynaptic neuron?
This is the neuron that ultimately releases a neurotransmitter in response to the action potential reaching the axon terminal
What is the Postsynaptic neuron?
This is the neuron that receives the nerve impulse from the presynaptic neuron by binding the neurotransmitters released from the presynatic neurons
What is synaptic vesicles? What
These vesicles are found in the presynaptic neuron within the synaptic knob and contains neurotransmitters
What are synaptic receptors?
These are the receptors found on the postsynaptic neuron that bind the neurotransmitters
What is the synaptic cleft?
This is the space between the presynaptic neuron and The post synaptic neuron
What are the 3 brain regions?
1) Cerebrum
2) Cerebellum
3) Brainstem
What is the CNS composed of?
Brain and the spinal cord
What are the lobes of the Cerebrum
1) Frontal
2) Parietal
3) Temporal
4) Occipital
What is the Cerebral cortex?
The outer edge of the Cerebrum
And composed of grey matter.
What is the Cerebrum?
It is the largest portion of the brain
- 83% of brain mass
- 2 hemispheres (right and left cerebral hemisphere) Now
What separates the frontal lobe?
-The Central sulcus forms the posterior boundary
What is the function of the frontal lobe?
Governs voluntary movements, memory, emotion, social judgment, decision making, reasoning, and aggression; is also the site for certain aspects of one’s personality
What separates the Temporal lobe?
Separated from the parietal lobe by the lateral sulcus
What is the function of the Temporal lobe?
Governs hearing, smell, learning, memory, emotional behavior, and visual recognition
What separates the Parietal lobe?
Central sulcus forms the anterior boundary
What is the function of the Parietal lobe?
Concerned with receiving and interpreting bodily sensations (such as touch, temperature, pressure and pain); also governs proprioception (the awareness of one’s body and body parts in space and in relation to each other)
What is the function of the Occipital lobe?
Concerned with analyzing and interpreting visual information.
What is the Insula
- Hidden behind the lateral sulcus
- Plays a role in many different functions, including perception, motor control, self awareness and cognitive functioning
Where is the Cerebellum located?
On the posterior region of brain and accounts for 11% of brain mass
What does it do?
- Receives input from the cerebrum, brain stem and body
- Processes input to provide balance, timing, balance/coordination and smooth, coordinated movement
How much grey matter in Cerebellum?
A large concentration amount of grey matter
What are the three regions of the Brain stem?
1) Midbrain
2) Pons
3) Medulla
What is the function of the brain stem?
-Controls nuclei that are involved in programmed and automatic behaviors necessary for homeostasis and survival.
What is the brain stem associated with?
Cranial Nerves
What are the functions of the Spinal cord?
-Provides two-way conduction to and from the brain
Spinal tract carry information (nerve impulses) from the spinal nerves of body to the brain OR information from the brain out to the body’s spinal nerves
-A reflex center for the body
Provides innate reflexes for the body,such as when you touch a hot item and rapidly pull your hand/arm away from it
What is the bundle of nerve roots extending from the end of the spinal cord?
Cauda Equina (Named because it looks like a horses tail)
Which part of the spinal cord is a physical cord
The spinal cord is a physical cord to the L1-L2 lumbar region. After that, it is a bundle of nerve roots called the cauda equina.
PNS: Spinal Nerves
How many pairs of spinal nerves originate from the spinal cord
-31 pairs divided by region
PNS: Spinal Nerves
How many nerve fibers in spinal cord?
Contains thousands of nerve fibers - mixed nerves
-Innervate all regions/parts of the body except for head
PNS: Cranial nerves
What are they classified as
Classified as peripheral nerves (Spinal nerves are the other classification)
- Innervate the head and neck except for the vagus nerve -Extends into abdomen
- Can be sensory and/or motor in function
PNS: Cranial Nerves
How many pairs of cranial nerves?
12 pairs of cranial nerves
-First two pairs attach to forebrain; rest attach to brainstem
What are the parts of the Autonomic Nervous System
1) Sympathetic
- “Fight or flight”
- increase heart rate, blood pressure, dilates pupils, etc
2) Parasympathetic
- “Rest and digest”
- Increases blood flow to digestive organs, slows cardiovascular system, etc.
What are taste and smell also referred as
Taste is also referred as gustation
Smell is also referred to as olfaction
What are receptors for taste and smell classified as
Chemoreceptors
which means initiated by chemicals within an aqueous solution
Taste and Smell receptors
Taste receptors- food chemicals dissolved in saliva
Smell receptors- airborne chemicals dissolved in membrane fluids within nose
What is hearing?
Involves our ability to transduce sound waves into electrical energy (action potentials
Where is the sense organ (allows for the process to occur), the cochlea, found?
Within the inner ear
Three areas of the ear
1) External ear
2) Middle ear
3) Internal ear
Vision: A heavy duty process within the body
- 70% of all sensory receptors
- 50% of the cerebral cortex is dedicated to visual processing
Where does Vision occur?
Within the eye
What is the process of vision?
- Incoming light is refracted (bent) to one point on the retina
- Photoreceptor cells(rods and cones) convert light (energy) into an electrical impulse (action potential)
- Action potential is transmitted via the optic nerve to the occipital lobe where the brain perceives vision
What are the Fibrous Outer Layers of the eye
- Sclera
- Cornea
What is the sclera?
Formed from dense connective tissue - is the outermost layer of the eye. Most of the sclera is white and opaque; it forms what is called “the white of the eye”. Blood vessels and nerves run throughout the sclera.
What is the cornea?
A transparent extension of the sclera in the anterior part of the eye. It sits over the iris (the colored portion of the eye) and admits light into the eye. It contains no blood vessels.
What are the parts of the Vascular middle layer of the eye?
- Iris
- Ciliary Body
- Choroid
What is the iris?
A ring of colored muscle; it works to adjust the diameter of the pupil (the central opening of the iris) to control the amount of light entering the eye
What is the ciliary body?
A thickened extension of the choroid that forms a collar around the lens. It also secretes a fluid called aqueous humor.
What is aqueous humor?
A fluid secreted by the ciliary body of the eye.
What is the Choroid
A highly vascular layer of tissue that supplies oxygen and nutrients to the retina and sclera.
What are the parts of the Neural Inner Layer of the eye?
- Retina
- Optic Nerve
What is the retina of the eye?
A thin layer of light-sensitive cells
What is the optic nerve?
Exiting from the posterior portion of the eyeball; also called cranial nerve II; transmits signals to the brain
Endocrine Glands
- Hypothalamus
- Pituitary gland (These two are often referred to as the H-P axis)
- Thyroid gland
What are the functions of the hypothalamus and Pituitary gland?
-They secrete a number of hormones that influence other endocrine glands.
What is the positioning of the glands.
-Tiny, pea-sized pituitary gland sits just underneath the hypothalamus. It lies cradled in the sella turcica, a cavity within the sphenoid bone.
Where is the thyroid gland located?
Butterfly shaped gland located within the neck; Resides in the neck, just below the trachea, where it is wrapped around the anterior and lateral portions of the trachea.
What does the thyroid do?
Produces and secretes: Thyroxine (T4), Triiodothyronine (T3), Calcitonin
-Controls body’s metabolism and calcium storage
What does calcitonin do?
Influences and helps regulate blood calcium levels.
Where is the parathyroid glands located?
Embedded in the posterior corners of the lobes of the thyroid. Most people have four parathyroid glands, but the number of glands as well as location can vary
What is the parathyroid gland?
Small glands on the posterior side of the thyroid gland.
What does the parathyroid gland do?
Secrete Parathyroid hormone (PTH)
What is the adrenal glands composed of?
1) Adrenal cortex (Inner portion of the adrenal gland)
2) Adrenal Medulla (inner portion of the adrenal gland)
What is the goal of the Adrenal glands?
Each region produces its own hormones but collectively help the body respond to stress.
Where are the adrenal glands located?
The two adrenal glands, again one on top of each kidney.
Where is the Pancreas located?
Located in the left lateral abdomen posterior to the stomach with its head tucked in the curve of the beginning of the small intestine (duodenum) and its tail reaching to the spleen
What are the roles of the pancreas
Has endocrine and exocrine roles
- Exocrine (called Acini): Digestive system; secretes enzymes into a duct that drain into the small intestine
- Endocrine: Secretes hormones into the bloodstream
What hormones are secreted by the Pancreas?
1) Insulin
2) Glucagon
What do the hormones of the Pancreas do?
- Help to regulate blood glucose (sugar) levels
- Produced by the cells called islets of Langerhans or Pancreatic islets (contains several different types of cells, the main ones being alpha cells, beta cells and delta cells)
What are the Gonadal organs?
1) Testes
2) Ovaries
What are the hormones of the testes?
1) LH: promotes testosterone production
2) FSH: stimulates sperm production
What are the hormones of the ovaries?
LH: Triggers ovulation and production of estrogen and progesterone
FSH: Stimulates follicle (egg) maturation and estrogen production
