Exam #3 M 4/6 at 7:30pm in BUR 106 before Exam #3: movement, and the immune system

Nerves allow us to perceive the environment while the brain integrates the incoming signals to determine an appropriate response. Fig 46.1 Responses can be release of hormones, change in cell activity, or muscle contraction Response

2 nerve signals for every movement: excitatory and inhibitory

How do muscles contract?

Fig 46.24 Excitatory neuro-transmitters released by motor neurons cause muscle cells to contract

Muscle cells are comprised of series of sarcomeres. Fig 46.19 Muscle cells are comprised of series of sarcomeres.

Each sarcomere is a repeating unit of actin and myosin proteins Fig 46.20 Each sarcomere is a repeating unit of actin and myosin proteins

As each sarcomere contracts, the muscle contracts Fig 46.20 As each sarcomere contracts, the muscle contracts

Neuro-transmitters released at nerve/ Fig 46.24 Neuro-transmitters released at nerve/ muscle junction cause calcium to be released in muscle

A third protein, tropomyosin controls when the muscle contracts Fig 46.23 A third protein, tropomyosin controls when the muscle contracts

ATP provides the energy for myosin movement along the actin Fig 46.22 ATP provides the energy for myosin movement along the actin

The contraction of muscle cells causes the muscle to contract

Nerves allow us to perceive the environment while the brain integrates the incoming signals to determine an appropriate response. Fig 46.1 Responses can be release of hormones, change in cell activity, or muscle contraction Response

Taking in food and oxygen exposes us to pathogens esophagus stomach

Pathogen: a disease causing agent

E. coli Phage virus Ebola Fungus from soil various pathogens

The Immune System Specific: Non-specific: B-cells -> antibodies T-cells Non-specific: barriers

Non-Specific Immune System Barriers: Skin- Dry Inhospitable Competition Secretions (lysozyme) Hairs and Mucus (protect openings) Traps particles, swallowed Stomach acid kills pathogens Fig 49.1

Skin protects us from most pathogens

Fig 49.1

Hairs and Mucus (protect openings) Traps particles Stomach acid kills pathogens esophagus stomach

Non-Specific Immune System Barriers: Skin- Dry Inhospitable Competition Secretions (lysozyme) Hairs and Mucus (protect openings) Traps particles, swallowed Stomach acid kills pathogens Fig 49.1

The Immune System Specific: Non-specific: B-cells -> antibodies T-cells Non-specific: barriers

The Specific Immune System

B-cells and T-cells move through the circulatory system scanning for pathogens

B-cells develop in bone marrow T-cells in the thymus Fig 49.4 B-cells develop in bone marrow T-cells in the thymus

B-cells make and secrete antibodies Fig 49.12 B-cells make and secrete antibodies

Fig 49.6a Variable region An Antibody Constant region

Antibodies recognize and bind to antigens Fig 49.7 Antibodies recognize and bind to antigens

B-cells male antibodies that bind to antigens marking them for destruction Fig 49.12 Marked for destruction by WBC

What about damaged or abnormal cells? Viral infections Cancer cells 11am class, this will be covered on F 4/3 What about damaged or abnormal cells? Viral infections Cancer cells Non-functional cells

T-cells recognize and destroy abnormal cells 11am class, this will be covered on F 4/3 T-cells recognize and destroy abnormal cells Fig 49.11

Immune System Overview 11am class, this will be covered on F 4/3 Immune System Overview