Practical 3

What are the two divisions of the nervous system?

CNS (brain & spinal cord) and PNS (nerves, ganglia, sensory receptors)

What neuroglia is in the CNS? Name them and note their functions

• Microglia - acts as macrophages

• Oligodendrocytes - myelinate axons in CNS

• Astrocytes - control chemical environment around neurons

• Ependymal cells - line cerebrospinal fluid-filled cavities

What neuroglia is in the PNS? Name them and note their functions

• Schwann - myelinate axons

• Satellite cells - surround cell bodies, provide support, macrophage

What is the most abundant neuroglia in the CNS?

Astrocytes

Whcih cell of the CNS have cilia?

Ependymal cells (help circulate CSF)

Oligodendrocytes and Schwann cells both myelinate axons, but oligodendrocytes myelinate _____(amount)_____, whereas Schwann cells myelinate _____(amount)______.

Multiple axons; one axon at a time

What are the three functional ways to classify a neuron?

• Sensory (towards CNS)

• Motor (away from CNS)

• Association (conduct impulses within the CNS)

What are the three structural ways to classify a neuron?

• Unipolar

• Bipolar

• Multipolar

What are the four major regions of the brain?

Cerebrum, diencephalon, brain stem, cerebellum

The cerebrum also known as cerebral hemisphere, is divided into?

Left and right hemisphere

Both left and right hemispheres are connected by what?

corpus callosum

What are the five lobes of the cerebrum?

Frontal, parietal, temporal, occipital, insula

What is the name of the structure that describes elevated ridges on the surface of the cerebrum?

Gyrus

What are the two types of gyri and what is the difference?

Sulcus - shallow/valley

Fissure - deeper sulcus

What are the structures and functions within the diencephalon?

• Thalamus - relay center for all sensory information, except smell

• Hypothalamus - regulation of body functions, hormones and emotions

• Epithalamus - contains pineal gland, which secrete melatonin

What are the structures and functions within the brain stem?

• Midbrain (Corpora quadridgemina, Cerebral aqueduct, Cerebral peduncles)

• Pons - connects cerebrum to cerebellum

• Medulla oblongata - regulates autonomicv functions (heart rate, blood pressure, breathing)

Corpora quadridgemina

2 superior colliculi for visual perception, 2 inferior colliculi for auditory perception

Cerebral aqueduct

provides a path for cerebrospinal fluid to flow

Cerebral peduncles

tracts that connect the pons to the cerebrum

________ is the smaller region, the _______ is bigger! (Cerebellum vs cerebrum)

Cerebellum; cerebrum

_______ is similarly split into two hemispheres which are seperated by a longitudinal fissure called the _______?

Cerebellum; vermis

The cerebellum also contains a thin superficial layer of _______ and a deep layer of ______.

gray matter; white matter

What are the three layers of the meninges? What about its subspaces?

1. dura mater (periosteal, meningeal)

   1. subdural space

2. arachnoid mater

   1. subarachnoid space

3. pia mater

What does the pia mater do?

Nourishes brain tissue because it contains blood vessels

List out this nmemonics: On once one takes the anatomy final - very good vacations are here!

1. Olfactory

2. Optic

3. Oculomotor

4. Trochlear

5. Trigeminal

6. Abducens

7. Facial

8. Vestibulocochlear

9. Glossopharyngeal

10. Vagus

11. Accessory

12. Hypoglossal

List out this nmemonics to match cranial nerves: Some say marry money but my brother says big brains matter more!

1. Olfactory (sensory)

2. Optic (sensory)

3. Oculomotor (motor)

4. Trochlear (motor)

5. Trigeminal (both)

6. Abducens (motor)

7. Facial (both)

8. Vestibulecochlear (sensory)

9. glossopharyngeal (both)

10. Vagus (motor)

11. Hypoglossal (motor)

What nerve is responsible for your sense of smell?

Olfactory

Nerve for the ability to taste and swallow?

Glossopharyngeal

Nerve for hearing and balance?

Vestibulocochlear

Nerve for changing lens shape and pupil size?

Oculomotor

Nerve for the ability to move eyeball (up, down, back, and forth)?

Trochlear

Nerve for the ability to move tongue?

Hypoglossal

Nerve for abducting eye?

Abducens

What are the layers of the eye? What structures are contained in each layer?

• Fibrous: sclera, cornea

• Vascular: choroid, ciliary body, iris

• Sensory: retina

What nourishes the eye?

Choroid because of blood vessels

What is the ciliary body?

Looks like a petal; produces aqueous humor and houses ciliary muscle for voluntary movement

What does the retina do?

absorb light and help reflect it from the eye

What cells are located in the retina?

Photoreceptors, bipolar cells, ganglion cells

What are the two type of photoreceptors and what function?

Rods - dim light

Cones - high light and color

What area has not photoreceptors and why?

Optic disc (blind spot), it’s where the optic nerve is connected to the eye

What is the pathway of light start with?

Light enters through the cornea → pupil → lens

The ______ controls pupil size to regulatre the amount of light entering the eye.

iris

_______ focuses the light on the retina.

Lens

Light reaches the photoreceptors located in the ______ which trigger the rods and cones.

retina

Photoreceptors stimulate _____ cells, which stimulate ganglion cells

bipolar

The axons of ganglion cells leave the retina via the _______.

optic nerve

Pathway of light:

1. Light enters eye through cornea → pupil → lens

   1. (Iris controls pupil size and regulate the amount of light into eye)

2. Lens focuses the light onto the retina

3. Light reaches the photoreceptors located in the retina wehich triggers the rods and cones

4. Photoreceptors stimulate bipolar cells → bipolar cells stimulate ganglion cells

5. The axons of ganglion cells leave the retina via the optic nerve

What are the three parts of the ear?

• Outer

• Middle

• Inner

What structures are located in the outer ear?

pinna, external auditory canal

What structures are located in the middle ear?

ossicles (incus, stapes, malleus), pharyngotympanic tube, tympanic membrane

What structures are located in the inner ear?

bondy labyrinth and membranous labyrinth

What structure seperates the external and middle ear?

Tympanic membrane

Define olfaction:

sense of smell

Define gustation:

sense of taste

What are the names of the receptors responsible for these two sense?

• Chemoreceptors!

• Molecules need to be dissolved in aqueous solution for chemoreceptors to transmit message to the brain

What are the three types of cells in olfactory epithelium?

1. Olfactory sensory neurons

2. Supporting cells

3. Olfactory stem cells

What are the three types of papillae?

1. Vallate papillae

2. Fungiform papillae (most abundant)

3. Foliate papillae

For gustation, the tongue contains:

Gustatory epithelial cells

True or false: each taste bud responds optimally to multiple types of taste

False

7 endocrine glands to know:

1. Pituitary

2. thyroid

3. adrenal

4. testis

5. pancreas

6. parathyroid

7. ovary

Most hormones are released to maintain homeostasis via a _______ feedback loop.

Negative

However, there are some instances where your body maintains a _______ feedback loop.

Positive

Give an example of negative feedback loop:

• When blood sugar gets too high, insulin is releases from the pancreas and lowers blood sugar levels

Give an example of a positive feedback loop:

During childbirth, uterine contractions lead to more oxytocin being released, which intensifies labor for birth.

For breastfeeding, prolactin stimulates more milk production.

What hormone does the hypothalamus secrete?

Makes a lot of hormones, but is stored in the posterior pituitary glands and secreted there. Anterior pituitary gland makes it’s own.

What are the three different types of stimuli that trigger the release of hormones?

• Humoral - changes in levels of chemicals in body trigger release of hormones

• Neural - nervous system stimulates endocrine glands to release hormones

• Hormonal - released hormones stimulate endocrine glands to release other hormones

What gland releases glucagon? What tissues and effect does it have?

Pancreas; targets primarily the liver and helps accelerate breakdown of glycogen into glucose

Name the hormones released by the ovaries and testes.

Ovaries: estrogen and progesterone

Testes: testosterone

True or false: the parathyroid gland is located anterior to the thyroid gland.

false

Prolactin for positive feedback loop.

When prolactin levels are high, it stimulates milk production. Oxytocin triggers milk letdown.