all midi 1

What are the 2 divisions of the peripheral nervous system

Afferent and efferent

What does the afferent division do

Relays sensory information to the CNS from the PNS

What does the efferent division do

Relays motor information from the cns to the pns

Describe the common sensory pathway

Stimulus- Receptor- neuron- CNS

Name the the 6 types of receptors

photoreceptors, mechanoreceptors, chemoreceptors, noicereceptors, thermoreceptors and osmoreceptors

What do photoreceptors do

receive wavelengths in the visible spectrum

What do mechanoreceptors do

mechanical energy

What do chemoreceptors do

Are sensitive to specific channels

What are noicereceptors

recept pain and tissue damage

What are thermoreceptors

HEat and cold

Osmoreceptors:

Solute concentration and osmotic activity

What receptor deals with olfactory and somatic senses

complex neural receptor

What receptor deals with vision, hearing, taste and balance

specialized senses receptor

List the 5 steps to transduce a ap in a complex neural receptor

1. Application of stimulus

2. Alteration of receptor membrane (na channels open)

3. Local current flow within the receptor (graded potential)

4. Change in frequency of action potential

5. Ap propagation to cns

List the 7 steps to transduction at the special senses receptor

1. Application of the stimulus

2. alteration of receptor membrane (ns channels close)

3. local current flow within receptor

4. release of neurotransmitter

5. change of post synaptic membrane potential

6. change in frequency of action potential

7. AP propagation to CNS

Define the receptive field

the part of a sensory space that can change the activity of the neuron

HOw do we perceive smell

We have different receptors and the combination of signals coming from stimulated neurons creates the perception of different cells

what are the 5 sensations in taste

Sweet, sour, salty bitter and umami

Parietal lobe feels what

sensation

Occipital handles what

Vision

temporal lobe

hearing/ object perception

Frontal lobe

Movement and cognition

How does smell travel through the brain

Through the olfactory bulb and into the olfactory cortex

how does taste

brainstem- thalamus - gustatory cortex

How does touch go

brainstem- thalamus- somatosensory cortex

Where does hearing go through in the brain

medulla- thalamus- auditory cortex

vision travels through brain

thalamus- visual cortex

How does balance go

Thalamus- vestibular apparatus

What are the 4 somatic sense

touch, proprioception, temperature and nociception

what does merkel’s receptors sense

steady pressure and texture

Meissener’s corpuscles sense

fluttering and stroking movements

Pacinian corpuscles sense

High frequency vibrations

ruffinis endings sense

Responds to skin stretch

Why might the adaption rate affect a sensory receptor

depending on the receptor some may adapt quickly and some will adapt slower to s consistent stimulus

which receptors have rapid adaption rates

Pacinian and meissner’s

which receptors are slower to adapt

Merkel and ruffini’s

Which receptors have a small receptive field

Merkel and meissner

Which receptors have a large receptive field

ruffini and pacinan

What is 2 pt discrimination

the smallest separation between 2 points on the skin that is perceived as 2 points instead of 1

regions with high tactile acuity have ——— receptive feilds

small

The benefit of convergence is

an amplified action potential which makes it easier for the signal to reach threshold

The dorsal root recieves

sensory information

the ventral root receives

motor information

What is a dermatome

A dermatome is an area of skin that is mainly supplied by nerve fibers from a single dorsal root of a spinal nerve

why are there no dermatomes on the face

because there are 12 pairs of cranial nerves which supply that area

which pathways synapse with their secondary neurons at the medulla

fine touch, proprioception and vibration

Which pathways synapse with their secondary neurons at the spinal cord

nociception, temperature and coarse touch

where is the primary somatosensory cortex located

on the precentral gyrus

the amount of space on the somatosensory cortex devoted to each body part is proportional to?

The sensitivity of that part

Where are thermoreceptors found

at the epidermis

thermoreceptors in the brain help?

maintain homeostasis

Cold/warm receptors are slow/fast to adapt

slow

the cold and warm receptors wont adapt outside of what range

20-40c

Describe beta fibers

Large, myelinated fibers which respond to mechanical stimuli

Delta fibers

Small, myelinated fibers which respond to intense mechanical or mechanotherapy stimuli (fast pain)

C fibers

small and unmyelinated (slow pain, heat and cold)

nociceptors have a high threshold what does this mean

the firing rate if nociceptors which continue to increase

What is hormone

A chemical signal secreted into the blood to act on a distant tissue

How does the endocrine system play a role in homeostasis

The endocrine system utlises hormones as effector or controlled variables which act by signaling to distant sites in the body

How is a hormone different than a neurohormone

hormones are secreted from a tissue/gland to act on a different part of the body by travelling through the blood. A neurohormone is secreted into the blood by a neuron

What is the main difference between a neurotransmitter and a hormone

Neurotransmitters travel through the neuronal synapse and are extremely rapid. Hormones travel through blood and are slower acting as the must be made, travel, bind and respond.

Explain the relationship between the hypothalamus and the posterior pituitary

the hypothalamus makes a hormone, this posterior pituitary then releases the hormone made by the hypothalamus.

Explain the relationship between the hypothalamus and the anterior pituitary

the hypothalamus makes the hormone and releases it into the portal system, this stimulates the anterior pituitary to make its own hormone. This antpit hormone is the released and goes to the target

How hormone release from the antpit is regulated

through the hypothalamic hypophyseal portal system

Where and what is the thyroid?

The thyroid is the colloid structure located in the neck which secretes hormones

What are the precursors for thyroid hormone synthesis

Thyroxine and iodine. these come from our diet and nutrition

Describe the feedback pathway modulating the levels of thyroid hormones in the blood.

Negative feedback. When T3 and T4 levels are low, TRH is released, which in turn stimulates the release of TSH. TSH stimulates the production of T3 and T4. once T3 and T$ levels go up, the amount of TRH and TSH decreases

Explain how thyroid hormones are produced and synthesized

Dietary iodide enters the follicle and travels into the colloid

Iodide and tyrosine combine to form T3/4

T3/T4 attach to thyroglobulin and stay in colloid

TSH binds to a follicular cell which triggers release of TG into follicular cell

t3/t4 is released from TG and travel through blood stream

is t3 and t4 active

T4 is active, t3 is inactive

What are the symptoms of hyperthyroidism

• high metabolic rate

• sensitivity to cold rooms'

• weightloss

• elevated hr

• graves disease

What are the symptoms of hypothyroidism

• low metabolic rate

• sensitivity to the cold

• weight gain

• low hr

• hashimoto thyroiditis

What are conditions which may cause hyperthyroidism

autoimmune disease, tumor or iron deficiency

Describe the effects whichT3/T$ have on the body

Effects almost every nucleated cell by influencing heartrate, increasing metabolism, making more hemoglobin and remodeling bones

What are the 5 types of steroid hormones

Mineralocorticoids, glucocorticoids, androgens, estrogen, progesterone,

when are steroid hormones released?

When their corresponding part of the adrenal gland is stimulated

how are steroid hormones produced

steroid hormones are produced from cholesterol in specific glands or tissues, modified by enzymes, released into the bloodstream, and then bind to receptors on target cells to influence various bodily functions.

Cortisol is a catabolic hormone what does this mean?

It causes the breakdown of macromolecules into its building blocks to affect the glucose levels in the body.

What effects does cortisol have on the muscles

Protein catabolism, turning proteins into amino acids to up levels of glucose in the blood

What effects does cortisol have on the livers

Glycogenesis, making glucose molecules out of the muscle and adipose provided in the organ

What effect does cortiosl have on adipose

Lipolysis- breakdown fat into triglycerides and then further into fatty acids and glycerol

How does cortisol effect the immune system

Immune suppression, being chronically stressed uses lots of energy

Why does glucose breakdown tissues

to make atp1

Describe the symptoms of Cushings disease

• hyperglycemia

• muscle atrophy and weakness

• thinning/tearing of skin

• stunted growth

• osteoporosis

• increased infection

What is Cushings’s disease

hypersecretion of cortisol

what is Addison’s disease

hyposecretion of cortisol

What triggers the release of a catecholamine

the triggering of the autonomic nervous system

What are the effects of increased ephinephrine on the body

Increase in glucogenesis

increased heartrate

relaxes lung airways

increased bp

What two major hormones are secreted by the pancreas

insulin and glucagon

Where is insulin and glucagon produced

in the islets of langerhans

what is the stimulus for release and the function of insulin

The stimulus for release of insulin is the fed state when glucose levels are high. this triggers the release for insulin release from fuel stores into blood

What is function of glucagon and its stimulus for release

The fasted state, when glucose levels are low. Tis triggers glucagon release and then glucose moves into cells to be used to make atp.

What are the cells which release insulin called

beta cells

What are the cells which release glucagon called

Alpha cells

Define Physiology

A branch of biology which deals with the normal functions of living organisms

What is an internal environment

Internal environments are environments in the body that are completely inside with no opening to the outside.

what is an external environment

An external environment is an environment outside the body or something in the body with an opening to the outside

Define Homeostasis

The ability of the body to maintain a relatively stable stable internal environment

Describe a negative feedback loop

A loop which works to maintain homeostasis and can shut itself back off

Describe the structures associated with the plasma membrane (glycoproteins/lipids)

aid in self recognition of the cell

Describe the structures associated with the plasma membrane (Transmembrane protein)

Aid in transporting stuff across the membrane