Nerves, Hormones, and Other Things

At 2 PM I resumed my overview of the body's systems with those dealing with control and regulation. The nervous system transmits electrochemical signals to different parts of the body to coordinate functions. It is typically divided into two parts. The central nervous system (CNS) processes information and initiates a response. It includes the brain and spinal cord. The meninges and cerebrospinal fluid protect these structures. The peripheral nervous system brings sensory information to, or carries output from the CNS. Sensory nerves cary imput to the brain from the environment, while motor nerves carry impulses to muscles/glands.

The peripheral nervous system is further divided into the somatic nervous system which coordinates voluntary functions and the autonomic nervous system which coordinates involuntary functions. The autonomic nervous system is even further divided into the sympathetic nervous system, which works when under stress to speed up functions, and the parasympathetic nervous system, which slows down functions.

The endocrine system, like the nervous system, deals with control and coordination of multiple body systems. However, it sends its messages within the body through hormones, which travel much slower (as I would learn later in AP Psychology). The organs of the endocrine system include the hypothalamus, the pituitary gland, the pineal gland, the thyroid and parathyroid glands, the thymus, the adrenal glands, the pancreas, and the gonads.

Unit four was short and described the levels of organization of the human body in greater detail. The human body is a hierarchal system, meaning it is made up of increasingly smaller subsystems. From smallest to largest, they are the following:

1. The chemical level (atoms, ions, small molecules)

2. The macromolecule level (large molecules)

3. The cell level (individual cells)

4. The tissue level (groups of cells which perform a specific function)

5. The organ level (tissues performing a higher-level function)

6. The organ system level (all of the organs involved in a vital function)

7. The organism level (entire body)

8. The population level (interactions with environment)

Unit five began with a review of basic chemistry. It is important to understand chemistry in order to understand biological processes at a molecular level. The atom is the basic unit of matter, containing a positive center (nucleus) surrounded by an electron cloud. The key biological elements are hydrogen, carbon, nitrogen, oxygen, phosphorus, and sulfur. Together, these elements make up 95 percent of the mass of a cell. Valence electrons are those in the outermost orbit involved in chemcial bonding. Electronegativity is the degree to which an atom will attract electrons in a chemical bond.

I ended my study session for the day at 3:00 PM.

#anatomy #capacitybuilding #seniorproject #physiology #chemistry