KHS 205 Final

Brainstem

connects the spinal cord to the base of the brain

The 3 parts of the brainstem

medulla oblongata, pons, midbrain

Medulla Oblongata

part of the brainstem that controls vital life-sustaining functions such as heartbeat, breathing, blood pressure, and digestion.

Pyramids

the 2 bulges of white matter in the anterior aspect of the medulla that decussate

Pons

relays info between cerebrum and cerebellum, helps control breathing along with the medulla oblongata

Midbrain (Mesencephalon)

part of the brainstem that connects the brainstem to the cerebellum; controls sensory processes

Superior & Inferior colliculi

2 swellings on the dorsal aspect of the midbrain

Superior Colliculi

involved in reflexive movements of the head, eyes, and body towards a stimulus

Inferior Colliculi

involved with hearing and the auditory pathway

Substantia nigra

an area of the midbrain that is involved in motor control and contains a large concentration of dopamine-producing neurons

Reticular Activating System (RAS)

a dense network of neurons located throughout the brainstem, responsible for maintaining consciousness and being alert, filters insignificant sensory info to prevent sensory overload

Cerebellum

POSTURE, COORDINATION, BALANCE

Diencephalon

contains thalamus, hypothalamus, epithalamus

Hypothalamus

controls many homeostatic functions (8) like body temperature, hunger and appetite, thirst and water intake, sleep-wake cycles, sexual drive, mood, release of hormones from the pituitary gland, and emotional expression.

Thalamus

the sensory relay center of the brain, neurons send sensory info to the appropriate area of the cerebral cortex to be processed

Epithalamus

consists of two structures, pineal gland and habenular nuclei

Pineal gland

secretes melatonin

Habenular nuclei

involved in smell and emotional responses to odors

Cerebrum

largest part of the brain, controls memory, voluntary activity, thought, perception, emotion

Frontal lobe

voluntary movement, speech production, problem solving

Parietal lobe

receives & evaluates touch, temperature, pressure, and pain

Temporal lobe

auditory processing, memory, language comprehension

Occipital lobe

vision

Insula

located deep in the brain, involved in taste

Telencephalon

cerebrum, lateral ventricle

Diencephalon

thalamus, hypothalamus, epithalamus, third ventricle

Mesencephalon

midbrain, aqueduct of midbrain

Metencephalon

pons, cerebellum, upper part of fourth ventricle

Mylencephalon

medulla oblongata, lower port of fourth ventricle

Flow of CSF through the brain

choroid plexus > lateral ventricle > interventricular foramen > 3rd ventricle > cerebral aqueduct > 4th ventricles > central canal > spinal cord

meninges

3 protective membranes that surround the brain and spinal cord

Dura Mater

most superficial membrane

Arachnoid mater

middle membrane, deep to dura mater

Pia mater

deepest meningeal layer

Olfactory nerve (I)

- sensory

- Function: sense of smell

- Injury = loss of smell

Optic nerve (II)

- sensory

- Function: vision

- Injury = loss of sight on affected side

Oculomotor nerve (III)

- motor

- Function: movement of the eye and eyelid, pupil constriction, pupil accommodation

- Injury = Inferior and lateral deviation of eye (leads to double vision), Eyelid drooping (ptosis), Pupil dilation, Blurred vision due to lack of accommodation

Trochlear nerve (IV) - SO4

- motor

- Function: movement of the eye (superior oblique muscle)

- Injury = difficulty moving the eye inferiorly and laterally

Trigeminal nerve (V)

- sensory & motor

- Function:

- sensory: sensation to the face and scalp

- motor: movement of the muscles of mastication

- Injury = weakness in biting/chewing, loss of facial sensation

Abducens nerve (VI) - LR6

- motor

- Function: movement of the eye (lateral rectus muscle)

- Injury = medial deviation of eye (leads to double vision)

Facial nerve (VII)

- sensory & motor

- Function:

- sensory: taste to anterior 2/3 of tongue

- motor: movement of the muscles of facial expression

- Injury = lost of taste (anterior 2/3), weakness in muscles of facial expression

ex) Bells Palsy

Vestibulochochlear nerve (VIII)

- sensory

- Function: hearing, balance, equilibrium

- Injury = loss of hearing, loss of balance, possible nausea

Glossopharyngeal nerve (IX)

- sensory & motor

- Function:

- sensory: taste to posterior 1/3 of tongue

- motor: innervation of pharyngeal (throat) muscles - swallowing and speech

- Injury = loss of taste (posterior 1/3), difficulty swallowing, decreased salivation

Vagus nerve (X)

- sensory & motor

- Function:

- sensory: sensation from pharynx (throat) and larynx (voice box)

- motor: control of soft palate, pharynx, laryngeal muscles, (swallowing and speech), contraction of thoracic and abdominal organs

- Injury = difficulty swallowing, hoarseness in voice, uvula deviation away from the side of dysfunction

Accessory nerve (XI)

- motor

- Function: movement of the trapezius and sternocleidomastoid muscles

- Injury = difficulty elevating scapula and rotating neck

Hypoglossal nerve (XII)

- motor

- Function: movement of the tongue and throat

- Injury = when protruded, tongue will deviate to the side of damaged nerve

sympathetic and parasympathetic

what are the two divisions of the ANS

Sympathetic Nervous System

what part of the autonomic nervous system has...

- Short preganglionic neurons and long postganglionic neurons

Thoracic and Lumbar region

where do the cell bodies of preganglionic neurons originate in the sympathetic nervous system?

Sympathetic chain (paravertebral ganglion) and Collateral ganglia

the two types of sympathetic ganglion

Parasympathetic Nervous System

what part of the autonomic nervous system has...

- Long preganglionic neurons, and shortpostganglionic neurons

Brainstem and Sacral region

where do the cell bodies of preganglionic neurons originate in the parasympathetic nervous system

Terminal Ganglion

parasympathetic ganglion

Acetylcholine (ACH)

- all parasympathetic and sympathetic preganglionic neurons release this neurotransmitter

- all parasympathetic postganglionic neurons release this transmitter

ACH's receptors

nicotinic and muscarinic

Nicotinic receptors

a receptor located in all postganglionic neurons

Muscarinic receptors

a receptor located on the effector organs only in the parasympathetic nervous system

Norepinephrine's receptors

adrenergic receptors

Adrenergic

a receptor located on the effector organs only in the sympathetic nervous system

Primary Somatosensory Cortex

area of the parietal lobe in the cerebral cortex where sensory input is registered

Somatosensory pathway

relays info from the somatic sensory receptors to the cerebral cortex - involves three neurons

First order neuron

sensory neurons conduct nerve impulses from sensory receptors into the spinal cord or brainstem

Second order neuron

conduct nerve impulses from the spinal cord or brainstem to the thalamus

Third order neuron

conduct nerve impulses from the thalamus to the cerebral cortex (primary somatosensory cortex) in the parietal lobe

Spinothalamic pathway

The route from the spinal cord to the brain that carries most of the information about skin temperature and pain (know how to draw out)

Dorsal Column-Medial Lemniscal Pathway

an ascending somatic sensory pathway that mediates information about fine touch, proprioception, 2 point discrimination (know how to draw out)

Corticospinal tract

major motor tract that controls voluntary movement of the body - 2 neuron chain (upper motor neuron & lower motor neuron)

Endocrine System

a network of glands and tissues that secrete hormones in order to maintain homeostasis within the body

Neural stimuli

signals from the nervous system

Humoral stimuli

chemical changes in the blood

Hormonal stimuli

hormones stimulate the secretion of other hormones

Pituitary gland

"master gland" - regulates the activity of several several other endocrine glands in the body

Hypothalamus

the master of the pituitary gland

7

how many hormones does the anterior pituitary gland produce/secrete?

2

how many hormones does the posterior pituitary gland secrete?

Thyroid Stimulating Hormone (TSH)

stimulates the thyroid gland to produce and secrete two thyroid hormones: triiodothyronine (T3) and thyroxine (T4)

Adrenocorticotropic hormone (ACTH)

stimulates secretion of the hormone cortisol from the adrenal glands

Follicle Stimulating Hormone (FSH)

acts on the gonads in males and females

- males: stimulates sperm production

- females: stimulates ovaries to secrete estrogen and produce oocytes (immature egg cells)

Luteinizing Hormone (LH)

acts on the gonads in males and females

- males: stimulates testes to secrete testosterone

- females: triggers ovulation and the release of progesterone and estrogen

Prolactin (PRL)

stimulates milk production by mammary glands from a woman's breasts after childbirth

- males: hypersecretion can cause erectile dysfucntion

- females: hypersecretion can cause absence of menstrual cycle

Growth Hormone (GH)

stimulates growth in childhood and is important for maintaining healthy body composition- in adults, it's also important for maintaining bone and muscle mass

Melanocyte Stimulating Hormone (MSH)

when secreted in excess stimulates increased melanin production in the skin (creates darkening of the skin)

oxytocin and antidiuretic hormone

hormones of the posterior pituitary

Oxytocin

- stimulates and enhances contraction of the smooth muscle of the uterus during childbirth

- stimulates milk ejection from mammary glands in response to a nursing infant

Antidiuretic hormone (ADH, vasopressin)

- regulates water balance in the body

- prevents dehydration- conserves body water by decreasing urine production

- acts on kidneys to return more water to the blood and constricts peripheral blood vessels which increases blood pressure

Diabetes Insipidus

a disease that results in decreased release of ADH in the posterior pituitary or a decreased response to ADH in the kidneys which leads to increased urination, thirst, dehydration, and fatigue

Triiodothyronine (T3), Thyroxine (T4), Calcitonin

What hormones does the thyroid secrete?

T3 and T4

these two hormones regulate metabolism, help regulate growth and maturation of several tissues

Hyperthyroidism

- increased secretion of T3 and T4 - increases the rate of metabolism

- symptoms: high body temp, weight loss, increased appetite, rapid HR, enlarged thyroid gland, anxiety/restlessness

Graves Disease

- an autoimmune disease that is the most common form of hyperthyroidism

- primary sign is bulging of eyes

Hypothyroidism

- decreased secretion of T3 and T4 - decreases the rate of metabolism

- symptoms: low body temp, weight gain, reduced appetite, reduced HR, reduced blood pressure, weak skeletal muscles, fatigue, dry hair & skin

Calcitonin

- reduces the concentration of calcium in the blood when levels are elevated

- inhibits osteoclasts and accelerates the uptake of calcium into the bone extracellular matrix

Parathyroid Gland

- 4 pea-sized glands located on the posterior aspect of the thyroid gland

- secretes parathyroid hormone

Parathyroid Hormone (PTH)

- increases the levels of calcium in the blood when levels are decreased

- stimulates osteoclast activity to release calcium in the blood

Pancreas

- located in the abdomen behind the stomach

- secretes hormones that regulate blood glucose levels

- contain alpha and beta cells

Alpha Cells

produce and secrete glucagon

Beta Cells

produce and secrete insulin

Insulin

lowers blood glucose by promoting the uptake of glucose into cells

Glucagon

raises blood sugar by stimulating the liver to break down glycogen (stored glucose) into glucose and releasing glucose into the blood

Diabetes Mellitus (type 1)

autoimmune condition in which insulin is not produced or is low due to beta cells being destroyed