Key Components of Reflex Arc, Endocrine Glands and Reproductive System

Running head: THE LIVING BODY (BIO)
The living body (bio)
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1THE LIVING BODY (BIO)
Task 3:
Key components of the reflex arc:
Reflex arc is the neurological unit of a neuron that carriers nerve impulses to the spinal
cord in response to a stimulus. For example, when a person touches a hot object, the person
automatically pulls their hand without conscious effort. This action is a type of reflex action
which is governed by five parts of a reflex arc. The five key components of the reflex arc are as
follows:
Receptor: Receptor is the sense organ in skin, muscle or other organs that responds to a stimulus
or signals in the external/internal environment. There are different types of receptors that can
respond to pain, chemical stimuli or taste.
Sensory neuron: Sensory neuron is the part that contains sensory receptor and carries impulses
towards the central nervous system (CNS). The activated sensory neuron send the signals all the
way to the spinal cord.
Interneuron: It is the component that carries nerve impulse within CNS and connects or relays
signals to the next neuron called the motor neuron.
Motor neuron: It is the component that carries impulse away from the CNS to the body and
connect it with a muscle.
Effector: Effector is the structure or organ by which an animal or person responds to the stimulus
such as muscle and gland (Hantman and Kaltschmidt, 2016).

2THE LIVING BODY (BIO)
Figure 1: Diagram of a reflex arc and its key component. Source: (Clusters 2017)
Glands of the endocrine system and the function of the hormones produced by them:
The following are the main glands of the endocrine system:
1. Pineal gland: Melatonin hormone is produced by the pineal gland and it plays a role in
maintaining the circadian rhythm or sleep-wake cycle of humans.
2. Pituitary gland: Pituitary gland is located at the base of the brain and it is a two lobe
structure. The anterior lobe of the pituitary gland secrete hormone like
adrenecorticotropic hormone (ACTH), Thyroid stimulating hormone (TSH), Follicle
Stimulating Hormone (FSH), Lutenizing Hormone (LH), Growth Hormone (GH) and
prolactin hormone. The main hormone secreted from the posterior pituitary gland is
oxytocin and antiduretic hormone (ADH). The function of the hormones released by
pituitary gland are as follows: