HAP Worksheet 3

Components of a reflex arc

1. receptor

2. sensory neuron

3. integration center

4. motor neuron

5. effector

What sensation does a hair cell detect

Hearing

What sensation do rods/ cones decect

vision/sight

what sensation do olfactory receptors detect

smell

what sensation do gustatory receptors detect

taste

what do muscle spindle and golgi tendon organs detect

proprioception

what sensation do thermoreceptors detect

temperature

what sensation do nociceptors detect

pain

what sensation do mechanoreceptors detech

touch

what sensation do pacinial corpuscles and meissners corpuscles detect.

vibration

what is the receptive field

area monitored by a single receptor cell

are there more hot or cold receptors in the skin

there are more cold receptors

what is the two point threshold

minimum distance necessary between two points of stimulation on the skin such that the points will be felt as two distinct stimuli

How are the stimuli reaching the photoreceptors optimised

the optics of the eye and the direction of gaze.

What is accomodation

When the ciliary muscles of the eye relax to reduce the thickness of the lens

Which division of the autonomic nervous system is responsible for dilation of the pupil

the sympathetic division

what is the scotoma and what causes it

the scotoma is the blind spot caused by the optic nerve

what are the five basic tastes

sweet

What is the knee jerk reflex

The knee jerk reflex (patellar reflex) involves stimulating the muscle spindle by striking the patellar tendon.

What nerves are involved in the knee jerk reflex

Femoral nerve (L2-L4)

What does a lack of a knee-jerk reflex indicate

nerve root compression

what is the ankle-jerk reflex

extension of the foot in response to tapping of the Achilles tendon

what does a lack of an achillies reflex indicate

S1 and S2 nerve root damage

What is the reflex pathway of the knee-jerk reflex

monosynaptic pathway. Stretching patellar tendon sends a signal through the L3-4 vertebrae to the quadriceps

what is the reflex pathway of the ankle-jerk reflex

monosynaptic pathway. stretching achillies tendon sends a sensory signal the the S1-2 nerve root

what is the Jendrassik manuever

a manuver done by clasping the hands together and pulling them apart

ipsilateral reflex

stimulus and response are on the same side of the body

contralateral reflex

sensory input from opposite side as motor output

Are the gustatory and olfactory pathways connected

no

what is a muscle spinde

A sensory receptor located within a muscle that detects changes in muscle length and the rate of that change, playing a crucial role in the reflex arc.

what is a golgi tendon apparatus

A proprioceptive sensory receptor located within tendons that detects tension and regulates muscle contraction to prevent injury.

What is an EMG

an electromyograph is a clinical test where electrodes are placed on the skin or inserted into muscles to measure the strength and frequency of action potentials in the muscle.

How do muscles co ordinate their activity to produce movement

what causes muscle fatigue

an ATP defecit, lactic acid buildup, and reduction in central drive

what is an coactivation

a phenomenon where activation of the agonist causes minor activation of the antagonist

what causes MND

a progressive dieases caused by the progressive loss of lower motor neurons. As is progresses motor neurons atrophy and skeletal muscle wastes away. It eventually leads to paralysis.

What causes myasthenia gravis

the bodies immune system produces antibodies that block/ destroy ACh receptors at the neuromuscular junction. This leads to rapid muscle fatigue.

What are the effects of Botulism

caused by infection with the botulinum toxin, the most toxic protein known to man. Acts on the meuromuscular junction, preventing the release of ACh.

What is Duchenne muscular dystrophy

caused by a mutation of the dystrophin gene on the X chromosome. Therefore it is more common in males, as they only have 1 X chromosome. Muscle dystrophy in general causes muscle degeneration and weakness. Dystrophin is an important structural protein that attaches the actin cytoskeleton of myocytes to the basal lamia surrounding them. This compromised membrana allows extracellular Ca2+ into the cell, causing mitochondria damage. Muscle fibres undergo necrosis, causing muscles to wither.

what does the latency period between stimulation and contraction represent

the time it takes for Ca2+ to be released from the sarcoplasmic reticulum into the sarcolemma, and for Ca2+ to bind to troponin, unblocking the myosin binding sites and allowing for excitation-contraction coupling to occur.

what are the receptors for the patellar and achillies reflexes

muscle spindles located in the quadriceps femoris and the gastrocnemius respectively.