Module 6: Exploring Age-Related Body Systems Changes
6.1: Cardiovascular System
This module is produced with the generous support of: John A. Hartford Center of Geriatric Nursing Excellence, UCSF School of Nursing.
This module in the biology of aging series focuses on the cardiovascular system. Differentiating changes that occur normally with age from those that can be modified is extremely important because cardiovascular disease is a major health problem for older adults; heart disease is the leading diagnosis for short stay hospital visits for people aged 65 and older and is the leading cause of death (Lakatta, 2002b).
However, although it remains a major contributor to poor health and death in old age, the death rates from heart disease have declined over the last several decades, as have those from stroke. One reason for this decline is the emphasis being placed on controlling hypertension. These data suggest that we can have an impact on cardiovascular function and that risk factors can be modified. In addition, we now realize that some changes that we thought were part of normal aging are really the result of deconditioning and disease.
Given these data, the objectives of the current module are to:
- Discuss changes in the structure and function of the cardiovascular system.
- Compare and contrast alterations in cardiac function that occur with age at rest with those that occur during exercise or under stressful conditions.
- Relate cardiovascular changes to relevant theories of aging and assess whether changes in the cardiovascular system lend support to such theories.
- Discuss the importance of hypertension in older adults and consider the implications for health teaching.
- Differentiate between systolic and diastolic dysfunction and discuss related clinical implications.
An understanding of basic cardiovascular anatomy and physiology is assumed.
6.2: Endocrine System
This module in the series on age related changes focuses on the endocrine system. Traditionally, the endocrine system included glands that secreted hormones that entered the blood or lymph to be carried to their target site to exert their effect. However, it is now understood that other tissues release chemical messengers that participate in the regulation and integration of body processes (Matfin, et al., 2002). Further, both the nervous and endocrine systems evolved in parallel; various parts of the two systems often use interchangeable components and messengers for communication; so neuroendocrinology studies secretions of neurons/organs whether or not they enter the blood stream. A better term for these chemical messengers is neuro-hormones.
While the list of organs and tissues that participate in regulating body processes is large, the focus of the current module will be on five endocrine glands outlined in the table below.
Targeted Endocrine Glands
- Adrenal Gland
Thus, the objectives of the current module are to enable the reader to:
- Discuss the effects of age related changes on the endocrine function of the:
- hypothalamus-pituitary (growth hormone; TSH; ACTH)-adrenal (cortisol; aldosterone; DHEA) system;
- thyroid (TSH, T4, T3); and
- pancreas (Insulin).
Evaluate the clinical implications of changes in the endocrine system with age as they relate to:
- replacement therapy with growth hormone and DHEA
- the evaluation of thyroid abnormalities
- the diagnosis and treatment of glucose intolerance and diabetes
- After completing the modules on the neurologic, endocrine, and musculoskeletal systems, evaluate their inter-relationships in how older adults respond to internal and external stressors.
6.3: Immune System
“A finger catches the sharp edge of an envelope; a noseful of tree pollen is accidentally inhaled; the latest virus finds host after human host. In all cases the assaulted body reacts through inflammation, a well known, but not well defined process, especially its molecular cascade of events. These events are orchestrated by chemokines and the other biochemicals of innate immunity, eventually engaging downstream immune cells and antigens involved with adaptive immunity. A person is born with an innate immune system, whereas acquired immunity is developed through lifelong contact with pathogens.” (Kreeger, 2003, p. 28)
This module in the Biology of Aging sequence deals with issues related to the responses noted above to some type of threat. It begins with a review of the immune system and age changes and then address some of the pathological conditions that are closely associated with alterations in immune function in the elderly. Specific objectives for the module are for participants to be able to:
- Identify components of the immune system that are influenced by normal aging processes and discuss how these alterations impact immune function and increase vulnerability to select health problems.
- Differentiate between changes that occur with age in the cellular versus humoral immunity.
- Utilize knowledge of the immune changes that occur with age in the development of interventions to prevent or to treat common problems.
6.4: Musculo-Skeletal System
The focus of this current module in the biology of aging series is on the musculo-skeletal system. However, as emphasized in the module focusing on changes in the neurologic system, the musculo-skeletal system is highly inter-related with the neurologic and endocrine systems making assessment of changes that occur and their clinical implications difficult to discuss in total isolation. We also now know that interventions can minimize the impact of age on the musculo-skeletal system and preserve function into advanced old age. With this in mind, the specific objectives for the current module are to:
- Describe age related changes in muscle tissue and its innervation, and the impact of these changes on strength and function.
- Delineate strategies to minimize or reverse age related decrements in muscle strength and function.
- Describe changes that occur in the skeletal system with age and factors that influence these changes.
- Describe how mechanisms underpinning the Free Radical and Maillard (glycosylation) theories of aging contribute to the age changes identified in the musculo-skeletal system.
After reviewing the modules on neurologic, muscle, endocrine, and skeletal changes with age, you should be able to evaluate their inter-relationships and overlapping impact on the functional status of older adults, and develop a plan of care when you review clinical cases.
6.5: Neurological System
This module in the biology of aging series focuses on changes that occur in the neurological system and how these changes influence both the functional status of older adults and approaches to providing care. At the same time, it is important to emphasize that the neurologic, muscle, endocrine, and skeletal systems are highly inter-related making assessment of changes that occur and their clinical implications difficult to discuss in total isolation.
For example, muscles continuously transmit information regarding position to the central nervous system and receive messages back to promote movement or re-alignment. Muscle activity and strength influence bone growth and development. And hormones, such as testosterone, estrogen, and growth hormone, influence muscle, bone, and brain growth and development.
Given this caveat, the objectives of the current module are to:
- Describe age related structural and metabolic/biochemical changes that affect neurons, glia cells, and synapses in both the central and peripheral nervous systems.
- Delineate the impact of age related changes in the neurologic system on neurologic and cognitive function.
- Distinguish normal cognitive changes that occur with age from dementing processes, and differentiate among types of dementing processes.
- After reviewing the modules on neurologic, muscle, endocrine, and skeletal changes with age, evaluate their inter-relationships and overlapping impact on the functional status of older adults.
Please note that a reference listing is found on the last page of this module. All references used (excepting those linked to during the module) are listed.
6.6: Renal System
Module Learning Objectives
The goal of this section is to describe the changes that occur in renal function that specifically affect clinical decision-making because they influence how the older adult adapts to alterations in fluids and to various pharmaceuticals. Because of the many functions of the kidney, alterations in renal function also influence endocrine function and the maintenance of hematopoiesis.
- Assess the effects of changes that occur with age in body fluid, thirst, hormonal regulation, renal structure, and renal function on: fluid and electrolyte homeostasis, acid-base balance, response to drug therapy, and renal function tests.
- Utilize knowledge of the effects of age changes in the development of interventions to prevent or treat common problems that occur with age, such as dehydration, and hyper- or hypo-natremia.